A0 a standard international paper size of 841 mm
1189 mm (33"463⁄4"), whose measurements
are derived from its area (1m2) and the ratio of
the lengths of its sides (1:
ffiffi
ffi
2p ); smaller derivative
sizes A1–A10 are half the area of the subsequent
size with the same ratio of side lengths (A1 is
841 mm594 mm etc.); see B0, C0.!130,!Table 6
Aaron’s rod architectural ornament depicting a rod
with foliage, almonds and sometimes a serpent
twined around it; from biblical episodes in which
Aaron placed his staff before the tabernacle,
after which it bloomed, and before the Pharaoh,
at which it became a serpent; see also staff of
Asclepius, Mercury.
!120
abaciscus Lat.; diminutive form of the word abacus;
a patterned tile or rectangular area in a mosaic.
abacus 1 Lat.; a flat squared slab at the very top of a
classical column, the upper part of a capital above
an echinus and below an entablature.!80,!81
see classical orders illustration.!78,!79
see classical capitals illustration.!81
see caryatid illustration.!76
see Romanesque and Gothic capitals illustration.!115
2 see abaciscus.
abatis see abattis.!104
abaton Gk; the sacred area in a classical Greek
temple, to which public entry was forbidden.
abattis a number of sharpened stakes embedded
into the ground in front of a fortification or castle
to inhibit oncoming attackers; also written as
abatis; see chevaux de frise, caltrap.!104
abattoir, slaughterhouse; a building in which
animals are slaughtered for the production of
meat and other products.
Abbasid architecture a classical phase in Islamic
architecture, the time of the caliph dynasty who
ruled Damascus and Baghdad from 750 to 1258
AD, characterized by lavish palaces and great
mosques.
see Abbasid spiral minaret illustration.
!67
abbey 1 a community of monks overseen by an
abbot, or of nuns by an abbess; also the main
buildings of this community.
see Carolingian abbey illustration.!98
2 see abbey church.!98
abbey church, abbey; the church of an abbey.
see Carolingian abbey church illustration.!98
abbozzo in painting, the sketching out of a
composition in a single colour as a guide for a
final work of art.
abele see white poplar.
aberration see chromatic aberration.
Abies spp. see fir.
Abies alba, see silver fir.
Abies balsamea, see balsam fir, Canada balsam.
Abies concolor, see white fir.
Abies sibirica, see Siberian fir.
ablution ritual cleaning of the body prior to religious
activity; a room in a temple associated with this.
!66
ablution fountain see wash fountain.
ablution trough see washing trough.
above ground see surface.
abraded finish see ground, honed, rubbed finish.
abrading the rubbing smooth or wearing down of a
surface with an abrasive.
abrasion the act of being rubbed or worn down.
abrasion resistance the resistance of a surface,
coating etc. to marking or scratching.
ABS acrylonitrile butadiene styrene.
abscissa in a system of coordinates, one of the two
coordinates as a distance from an axis; usually
the distance of a point from the Y-axis, measured
parallel to the X-axis.!127
absidiole see apsidiole.!95,!98
absinthe green a shade of greyish green named
after green absinthe liqueur, flavoured by the
wormwood plant, Artemisia absintium.
absinthe yellow a shade of greyish yellow named
after yellow absinthe liqueur; see also absinthe
green.
absolute humidity the moisture content of air
measured as the weight of water vapour per unit
volume of air; SI units are kg/m3.
absolute zero the lowest attainable temperature,
equivalent to 0C kelvin or273.16 C.
absorber 1 in acoustics, any component, unit or
surface treatment for absorbing sound in a space.
2 see resonator.
absorbing glass see tinted solar control glass.
absorption1a physical phenomenon, the soaking up
of a liquid by a porous solid, a gas by a liquid, or
energy in the form of sound, heat or light by matter.
2 see sound absorption.
3 see attenuation.
absorption coefficient 1 in room acoustics, a
measure of the capacity of a material or construction
to absorb sound of a given frequency incident
upon it.
2 see sound absorption coefficient.
absorption unit see metric sabin.
absorptivity 1 a material property, the ability of a
solid to absorb a liquid, radiation, energy etc.
2 thermal absorptivity.
3 see light absorptivity.
abstract art a branch of art which is nonrepresentational
or freely represents reality in the
form of patterns and colours.
abutment 1 the meeting place, joint or lap of two
adjacent components, parts of construction etc.
2 the planar joint formed by two surfaces or edges
placed adjacent to or touching one another.!3
3 the meeting of the upper edge or verge of a
pitched roof and a balustrade, parapet or upper
wall surface; especially the vertical surface or
structure which rises from this.
4 the part of a loadbearing system or member from
which loads are supported.
5 walling or support on either side of the impost of
an arch to prevent it from splaying outwards.!22
6 see bridge abutment.!31,!64
7 see end abutment.
abutment flashing in roof construction, a vertical
sheetmetal flashing used with profiled sheet or
interlocking tile roofing at an abutment.!56,!57
abutting tenon joint, butt tenon joint; a timber
joint in which the grain ends of two tenons inserted
in a common mortise from opposite sides abut
each other.!5
abyss see fess point.
!124
AC see alternating current.
acacia [Acacia spp.] a genus of bushes and hardwood
trees from warm climates.
Acacia melanoxylon, see Australian blackwood.
academic relating to higher education or an academy;
of art which follows the formal conventions of the era.
academy a place of higher education in the arts; a
scientific or cultural society or institution.
acanthus Lat.; carved and decorative ornament
found especially adorning classical Corinthian capitals,
based on stylized leaves of the Mediterranean
acanthus plant, Bear’s breech or brank-ursin

[Acanthus molla, Acanthus spinosa]; akanthos in
Greek.!81,!82,!121
Accadian period see Akkadian period.
accelerated curing see heat treatment.
accelerated set in concretework, an increase in the
rate of stiffening during the setting of concrete.
accelerating admixture 1 see set accelerating
admixture.
2 see strength accelerating admixture.
acceleration the progressive increase in velocity of
a moving body, in units of m/s2.
acceleration lane see merging lane.
accelerator 1 see set accelerating admixture.
2 see strength accelerating admixture.
accentlighting interior lighting designed to illuminate
or accentuate features in a room, such as artwork,
architectural details and furnishings.
acceptance in project administration, the agreeing
by a client to a contractor’s tender bid thereby
creating a binding contract.
accepted risk, excepted risk; in project administration,
known risks in construction such as uncertain
ground conditions etc., referred to in the building
contract, for which the client accepts liability.
acceptor a metal or extruded plastics product
attached at the edge of a wall opening, to which
a door or window frame can be easily attached.
access, 1 passage; internal or external circulation
space leading to a building, opening or technical
installation, or used as a route.
2 see entry.
3 see site access.
4 see vehicular access.
5 in computing, the means of getting to and
handling information, often involving the use of
codewords.
access balcony, walkway; a long approach balcony
or external corridor providing access to the front
doors of flats or other units of accommodation in
an apartment block.
see balcony-access flats in residential building
illustration.!61
access barrier see vehicular barrier.
access bridge see walkway.
access control any of a number of security systems
using locks, surveillance equipment and card
readers within buildings or restricted areas to
allow the circulation of authorized persons but
inhibit the passage of intruders.
accesscover a covering hatch, plate or construction
attached over an access opening in a drainage pipe,
duct or vessel.
access door, access window, trapdoor; a removable
panel in formwork which allows for internal
inspection, cleaning etc.
access floor, 1 cavity floor, raised floor; flooring
supported above a main floor structure to allow for
the passage of electric and computer cables, ducts
and other services beneath.
see access floor illustration.!44
2 raised access floor, see platform floor.!44
access gallery see access balcony.
see gallery-access flats in residential building
illustration.!61
access gully a drainage gully with a rodding eye for
cleaning.
accessibility 1 in town and traffic planning, a measure
of how easily and by which mode of transport a
particular area can be reached.
2 the ability of a component or construction to be
easily accessed for maintenance, repair, replacement
etc.
access ladder 1 a ladder attached to the external
wall of a building to provide maintenance access to
the roof; also called a roof access ladder.
2 see roof ladder.
3 see chimney ladder.
!54
4 loft ladder, see disappearing stair.
access order in town planning and land management,
an order issued by a local planning authority
to ensure legal public access to private land for
throughfare, recreation etc.
accessory any small components used to affix
or supplement a construction, or fixings and
trim supplied with a product, component or
system.
access pipe a drainage pipe with an opening for
cleaning.
access platform see gantry.!54,!61
access stair, service stair; a secondary stairway
providing access to plant or other installations.
access time, search time; in computing, the time
taken for a computer or search engine to find
required data.
access window see access door.
accidental air see entrapped air.
accidental colours see afterimage.
accidental point in perspective drawing, any
additional vanishing points not on the axes of the
main points.
accommodation road a road through private land
which another person or persons have the legal
right to use, usually as a route to their own land,
and often in return for land concessions.
accordion door a folding door with a number of
hinged vertical panels which fold together when
the door is open.
!50
account 1 a written record showing financial
transactions as tables of figures.
2 an arrangement with a bank or other financial
establishment whereby money or assets are kept.
3 a personal arrangement with a supplier, shop or
other commercial facility for the payment of goods,
services etc.
accountancy, accounting, bookkeeping; the
upkeep of the financial records of a company or
organization.
accountants,bookkeepers;professionals employed
to look after the books and accounts of a company.
accounting see accountancy.
accounting period a set period after which
revenues and expenditures for a company are
calculated.
accoupled in classical architecture, a description of
columns or pilasters arranged in pairs, twinned or
joined together.
Accrington brick a hard, dark red brick made of
shale from East Lancashire in England, used for
engineering and industrial purposes.
accuracy an expression of the range and magnitude of
error in measurement, manufacture of products etc.
Acerspp. see maple.
Acer nigrum, see black maple, hard maple.
Acer pseudoplatanus, see sycamore.
Acer rubrum, see red maple, soft maple.
Acer saccharinum, see silver maple, soft maple.
Acer saccharum, see hard maple, sugar maple.
acetal see polyoxymethylene.
acetate a salt or ester of acetic acid, used for many
plastic household products, as cellulose acetate for
record discs and clear plastic sheet etc.; acetate
compounds included as separate entries are listed
below.
amyl acetate.
cellulose acetate, CA.
lead acetate.
polyacetate, see polyoxymethylene, POM.
polyvinyl acetate, PVA.
acetone a colourless, strong-smelling, volatile and
flammable liquid distilled from organic compounds
and used as a solvent.
acetylene black a form of the pigment carbon black
made by cracking acetylene gas under heat.
Achaean art, Achaian art; art predating that of the
Dorians, produced in Thessaly, ancient Greece, by
the Achaean peoples from 2000 to 1100 BC.
4 Accadian period

Achaemenian art art with Assyrian influences
predating the age of Alexander the Great,
produced in Persia by the Achaemenid peoples
from 559 to 330 BC.
Achaian art see Achaean art.
acheiropoeitos a sacred image in Byzantine art, not
created (or thought not to have been created) by
man; akheiropoeitos in Greek.
achromatic see colourless.
achromatic colour in colour science, a mixture of
varying degrees of solely black and white.
acid a sour, alkali-neutralizing chemical substance
capable of corroding metals.
acidcleaning a cleaning treatment for metals using
sulphuric, phosphoric or citric acids in combination
with surfactants to remove contaminants, rust and
scale from the surface.
acid-curing lacquer a two-pack lacquer used on
interior timber surfaces, based on urea or melamine
formaldehyde resins; see next entry.
acid-curing paint a two-pack paint for interior
use based on urea or melamine formaldehyde
resins, with good surface hardness and long
pot-life and which hardens by blending with an
acid.
acid dew point the temperature at which
combustion gases rich in sulphur and chlorine
condense as liquid acid.
acidicrock, acid rock; types of igneous rock whose
silica content is greater than 66%.
acidity, degree of acidity; the acid level of a soil,
solution etc., as measured by obtaining its pH level.
acid rock see acidic rock.
acid wash a cleaning treatment for concrete
and stonework by sponging with a solution of
acid salts.
ACM see polyacrylate rubber.
acorn an ovoid finial resembling the fruiting body of
an oak tree; used as an ornamental terminating
element for a balustrade or pier etc., often
unembellished; see pineapple, pine cone.!121
acorn nut see cap nut.!37
acoustic, acoustical; dealing with or based on
sound, or the treatment of sound.
acoustic absorber see absorber, muffler.
acoustic absorption see sound absorption.
acoustic absorption coefficient see sound
absorption coefficient.
acoustical see acoustic.
acoustical analysis a study of the sound insulating,
absorbing and reflecting characteristics of a building
or space, or a project at design stage.
acoustical design the design of a building or
space with respect to absorption, insulation or
enhancement of sound.
acoustical glass see sound control glass.
acoustical treatment see acoustic treatment.
acoustic attenuation see attenuation.
acoustic attenuator see muffler.
acoustic board softboard whose surface is shaped,
perforated or machined to improve its properties of
sound absorption.
acoustic ceiling a ceiling designed to provide
sound insulation or absorption for a space.
acoustic consultant see acoustician.
acoustic control glass see sound control glass.
acoustic engineer see acoustician.
acoustic glass see sound control glass.
acoustician, acoustic engineer; an expert
who provides professional consultancy on acoustic
matters.
acoustic insulation see sound insulation.
see soundproofing in floors and flooring illustration.
!44
acoustic intensity see sound intensity.
acoustic intensity level see sound intensity level.
acoustic isolation see sound insulation.
acoustic level see sound level.
acoustic level meter see sound level meter.
acoustic mortar see acoustic plaster.
acoustic panel a panel designed to absorb sound
and thus regulate the acoustic quality of a space.
acoustic plaster plaster containing lightweight
or other porous aggregates, used for its acoustic
properties, especially sound absorption; also called
acoustic mortar.
acoustic plasterwork plasterwork containing
aggregate which has acoustic properties; finished
work in acoustic plaster.
acoustic power see sound power.
acoustic power level see sound power level.
acoustic pressure see sound pressure.
acoustic pressure level see sound pressure level.
acoustic propagation see sound propagation.
acoustics 1 the study of sound and hearing.
2 the properties of a room pertaining to sound.
3 see acoustical treatment.
4 see room acoustics.
acoustic spectrum see audio spectrum.
acoustic treatment, acoustics; physical or spatial
measures, materials or components added to affect
the acoustic perception and performance in a space
with respect to sound insulation, absorption and
reflection.
acre an imperial unit of area equivalent to
4047 m2.
acrolith in classical Greek architecture, a statue
whose head, hands and feet are of marble fixed to
a timber torso.
acropodium Lat.; in classical architecture, a pedestal
or plinth for a statue; akropodion in Greek.
acropolis in classical Greek architecture, a city
stronghold or fortress constructed on higher
ground than surrounding urban fabric.!94
across the grain perpendicular to the general
direction of the grain in timber.
acroter see acroterion.!78
acroterion, acroter; in classical architecture, a plinth
or pedestal for statues, set at the apex or eaves of a
temple; also often the statues or ornaments themselves;
plural acroteria; Latin form is acroterium,
Greek is akroterion.!78
see acroterion in classical temple illustration.!86
acroterium Latin form of acroterion.!78
acrylate adhesive acrylic-based polymer adhesive
used for soft plastic seams and adhesive
tapes.
acrylic a synthetic polymer resin used in plastics,
paints, adhesives and textiles.
acrylic baking enamel see acrylic stoving enamel.
acrylic cellular sheet, cellular acrylic sheet;
cellular sheet glazing or cladding manufactured
from transparent acrylic resin.
acrylic coating see acrylic finish.
acrylicfinish, acrylic coating; any surface covering
or coating, such as tiling, boarding and paints,
whose finish is acrylic.
acrylicflooringcompound a hardwearing flooring
for sports halls, corridors etc. laid over concrete
floor slabs as a mixture of liquid acrylic, powdered
hardener and fine aggregate.
acrylic paint emulsion paint based on a dispersion
of acrylic in water.
acrylic polymer flooring see acrylic flooring
compound.
acrylic powder coating, stoved acrylic; a
hardwearing decorative coating whose binder is
acrylic resin, applied to metal components as a
powder and baked on.
acrylic primer acrylic paint used as a primer or
undercoat.
acrylic rubber see polyacrylate rubber.
acrylic sealant an acrylic-based flexible sealant
used for dry applications.
acrylic sheet strong translucent or opaque
lightweight sheet of polymethyl methacr
plastics used for glazing and cladding; marketed as
Perspex and Plexiglas.
acrylicstovingenamel, acrylic baking enamel; a
hardwearing paint coating used in the automotive
industry, based on acrylic resin applied to metal
surfaces as a liquid spray and baked on.
acrylonitrile butadiene styrene, ABS; a tough,
strong thermoplastic used for waste pipes, garage
doors, small vehicles and taxi-cab roofs.
actinium a radioactive, silver-white, metallic chemical
element, Ac, which glows in the dark.
action area in town planning, a particular area
designated by a planning authority to merit special
change such as development, redevelopment or
improvement.
activated carbon, activated charcoal; granular
or powdered forms of porous carbon or charcoal
processed to remove tarry components, used for
adsorbing gases and odours from air, or dissolving
contaminants from liquid solutions.
activated charcoal see activated carbon.
activated sludge organic mass produced from
sewage aerated by blowing air through it, used in
the treatment of waste water for the digestion of
incoming sewage.
activated-sludgeprocess the biological treatment
of waste water using organisms in aerated sludge to
digest the solid matter from incoming sewage.
active earth pressure the pressure of earth acting
against the side of a wall and against which it
provides resistance.
active fire protection mechanical or electronic
control systems such as sprinklers, fire alarms etc.
for indicating the presence of or extinguishing
hazardous fires in buildings.
active leaf the door leaf in a double door usually
used for throughfare.!50
activity analysis a study of the overall patterns of
behaviour and activities of a particular user group
such as inhabitants, consumers or occupants, used
as a basis for the formulation of a design brief or
town plan.
activity space, hobby room, recreation room;
a space in a residential building or dwelling primarily
used for leisure activities and hobbies.
act of God see force majeure.
actual size the size of an object as obtained by
measurement; see also nominal dimension.
acute angle an angle of less than 90.
acute arch see lancet arch.!24
Adam style a style in interior decoration in England
from 1760 to 1770 named after the Adam brothers,
John, Robert and James, and characterized by classical
motifs and bold colours.
adapter see adaptor.
adaptive use in town planning, the change in use
or function of a building from that for which it was
originally designed.
adaptor,adapter;1 a device for converting mains
current to that suitable for operating electronic
devices.
2 see plug adaptor.
3 see flue adaptor.
!58
addendum a separate explanatory statement intended
to clarify, amend or supplement a document, drawing
etc.
addition 1 the process of adding numbers together
to produce a sum.
2 an extension to an existing building.
additional work see extra work.
addition polymerization, polyaddition; the
chemical joining together of two or more molecules
of a compound such that the molecular weight
of the polymer thus formed is a multiple of that of
the original compound; the general form of
polymerization.
additive a substance added to a material or process
to modify its chemical or physical properties.
additive mixture in colour science, lighter colours
formed when beams of coloured light are
combined, thus adding spectral components
together.
additive order the building of Romanesque and
early Gothic churches with additional transepts,
chapels and chancels.
!97
addorsed a description of ornament or sculptured
figures standing or situated back to back; see also
affronted.!122
addressable system, intelligent fire alarm; an
electronic installation for indicating the location
and severity of an outbreak of hazardous fire in a
building.
adhering knot see tight knot.
adhesion, bond; the action of sticking together; the
strength of the attractive or fastening force evolved
between a surface material or coating and its
backing, or between two components which have
been glued or bonded together.
adhesive a sticky solid or liquid bonding
substance used for the firm sticking, surface
joining and holding together of materials and
components; the words adhesive and glue are
generally synonymous, although adhesive is
often applied to more technologically advanced
products, while glues are often of plant or animal
origin; a cement is an inorganic adhesive
whichsetsinhard,brittleform;typesofadhesive
included as separate entries are listed
below.
aerosol glue, see spray adhesive.
albumen glue.
anaerobic adhesive.
animal glue.
aqueous adhesive, see water-borne adhesive.
bituminous adhesive.
bone glue.
brushing adhesive.
casein glue.
cassava.
cellulose adhesive.
cold curing adhesive.
cold glue, see cold setting adhesive, cold curing
adhesive.
cold setting adhesive.
collagen glue, see animal glue.
contact adhesive.
cyanoacrylate adhesive.
elastomeric adhesive.
emulsion glue, emulsion adhesive.
epoxide resin adhesive, see epoxy resin adhesive.
epoxy adhesive, see epoxy resin adhesive.
epoxy glue, see epoxy resin adhesive.
epoxy resin adhesive.
film adhesive, see film glue.
film glue.
fish glue.
gluten glue.
gun applied adhesive.
gunnable adhesive, see gun applied adhesive.
hide glue.
hot-melt adhesive, see thermoplastic adhesive.
hot-melt glue, see thermoplastic adhesive.
hot setting adhesive, see thermosetting adhesiv
PVA glue, polyvinyl acetate glue.
resin adhesive, see synthetic resin adhesives.
resin glue.
resorcinol formaldehyde glue.
rubber adhesive, see elastomeric adhesive.
rubber glue, see elastomeric adhesive.
rubber solution.
Scotch glue.
single spread adhesive, see one-way stick adhesive.
solvent adhesive.
solvent-based adhesive, see solvent-borne adhesive.
Solvent-borne adhesive.
soya glue.
spray adhesive.
starch adhesive.
structural adhesive.
super glue, see cyanoacrylate adhesive.
synthetic resin adhesive.
synthetic rubber glue, see elastomeric adhesive.
thermoplastic adhesive.
thermoplastic glue, see thermoplastic adhesive.
thermosetting adhesive.
two pack adhesive, two component adhesive, two
part adhesive.
two-way stick adhesive.
urea formaldehyde glue.
vegetable glue.
water-borne adhesive.
waterproof glue, see water-resistant adhesive.
waterproof adhesive, see water-resistant adhesive.
water-resistant adhesive.
water-based adhesive, see water-borne adhesive.
wood adhesive.
wood glue, see wood adhesive.
adhesive failure, bond failure; the failure of a
glued joint due to a reduction in bonding between
a glue or binder and glued parts.
adhesiveness the ability of a glue to provide a
bond between two surfaces.
adhesive tape paper or plastics tape with adhesive
on one or both sides and manufactured
in rolls; used for fastening, fixing, masking, insulating
etc.
adhocism a term coined by the architect Charles
Jencks to describe modern eclectic styles of
architecture which contain random references and
historical motifs.
adiabatic referring to a thermodynamics process
which occurs without the transfer of heat.
adit, aditus (Lat.); a passage or entranceway,
especially one to a Roman building.!89,!90
aditus Latin form of adit.!89,!90
adjacent building a building on a site next to that
of a proposed or existing building, such that there
is space between the two.
adjoiningbuilding a building on a site next to that
of a proposed or existing building, such that they
are physically joined to one another.
adjustable the ability of a device, tool, machine,
furnishing etc. to be able to be adjusted to suit
the needs of the user or a process.
adjustable item an item in a bill of quantities for
which provided information is insufficient and
whose quantities are subject to reassessment.
adjustable prop see telescopic prop.!30
adjustable set square in technical drawing, a set
square in which the angle of the hypotenuse can be
adjusted by a sliding mechanism.!130
adjustable spanner a spanner with screwadjustable
jaws to suit a range of widths.
adjustable wrench see adjustable spanner.
adjustment see formula price adjustment.
adjustment screw in field surveying, a screw
on an optical levelling instrument for making
fine adjustments; a similar component on other
devices.
administration, management; the overseeing,
planning and direction of affairs and personnel in
an organization.
administrative building a building connected to
an institution, public building or industrial complex,
from which it is governed.
admiralty brass an alloy of copper and zinc with
additional tin to improve corrosion resistance and
increase strength.
admixture a material added in small quantities to
affect the properties of a concrete or mortar mix;
types of admixture included as separate entries are
listed below; see also agent.
accelerating admixture, see set accelerating
admixture, strength accelerating admixture.
air-detraining admixture.
air-entraining admixture.
anti-foaming admixture.
antifreezing admixture.
bonding admixture.
colouring admixture.
corrosion inhibiting admixture.
expansion producing admixture.
flocculating admixture.
foam forming admixture.
fungicidal admixture.
gas forming admixture.
high range water-reducing admixture, see superplasticizing
admixture.
mortar admixture.
permeability-reducing admixture, see pore filler.
plasticizing admixture.
set accelerating admixture.
set retarding admixture.
strength accelerating admixture.
superplasticizing admixture.
thickening admixture.
water-reducing admixture.
water-resisting admixture.
waterproofing admixture, see water-resisting
admixture.
adobe 1 clay and unfired brick which has been
baked in the sun; see mud brick.
2 forms of construction making use of this.
ADP acronym for automated data processing, see
computing.
adsorption1 the intake of a liquid or gas by a solid.
2 a water purification treatment in which water is
percolated through solid granular material, to
which impurities adhere.
adularia a transparent variety of the mineral
orthoclase or potash feldspar found in the Alps.
see moonstone.
aduton Greek form of adytum.!85
advance, advance payment, prepayment; a
payment made prior to receipt of goods or
services, such as that paid by a client to a contractor
after the contract is signed but before the start
of work.
advanced decay, typical decay; a late stage of
decay in wood indicated by softening and loss
of structural strength.
advanced work an outer defensive structure built
close enough to main fortifications to gain covering
fire from it; an outwork or first line of defence; also
called a forework.!104
see fortification illustration.!104
advance payment see advance.
advent cross see tau cross.!117
adventure playground an area of landscaped
ground, often with climbing frames etc., for
children to play on.
advocacy planning in town planning, the
preparation of plans or planning proposals on
behalf of an organization, interest group or a
community rather than by an official agency.
adyton see adytum.!85
adytum, sanctuary; Lat.; in classical architecture,
the most sacred inner chamber of a Greek temple
B
B0 a standard international paper size of 1000 mm
1414 mm (39"55"), used for posters and card;
successive smaller sizes B1–B10 are derived by halving
the area of the next size up; see A0, C0. Table 6
baby blue a shade of pale greyish blue which takes
its name from the colour of the clothes of infant
boys.
Babylonian period a period in Mesopotamian art
from the time of the Kassite invasion in c.1800 BC
culminating with the onset of Persian rule in
539 BC.
Bacchus, staff of see thursus.!120
back 1 the reverse, inferior or secondary face of a
piece, component, building etc.
2 worse face; the surface of a timber board to the
reverse side of the outer, usually finished surface.
3 the edge of a sawtooth adjacent to its cutting
edge.
4 see window back.
backbed in glazing, bedding compound or a proprietary
product applied to a rebate in a window frame, against
which a pane is fixed.
back boiler 1 in a heating system, a boiler fitted to
the rear of a solid fuel heater, which provides the
thermal energy for water heating.
2 see high output back boiler.
back clearance in glazing, the horizontal distance
between the inner face of the pane or glazing unit
and its supporting frame.
back cut veneer decorative veneer formed by
peeling the inner side of a half log or flitch
off-centre on a lathe.!10
backdraught, smoke explosion; a rush of air into a
room containing smouldering contents due to the
opening of a door during a hazardous building fire,
causing spontaneous ignition.
backer see back-up material.
backfill, fill; in sitework, earth replaced and
compacted into an excavation to cover subsoil
foundations and services once they have been laid.
backflaphinge a hinge whose leaves are long rather
than tall, used for applications such as furnishings and
table flaps where a butt hinge is insufficient.!38
backflow a phenomenon in which liquid flows along
a pipe or channel in the reverse direction to that
intended, caused by pressure or a partial vacuum;
see also backsiphonage.
backflow prevention device a device for
inhibiting the backflow of water in a drainage or
sanitary installation.
backflow valve, 1 back-siphonage preventer,
backwater valve, back-pressure valve; a check
valve in a water system which allows water in a
pipeline to flow in one direction only.
2 see pipe interrupter.
back form in concreting, formwork or formwork
surfaces used in locations which remain hidden in
the final structure; back formwork, in full.
backgutter in roof construction, a channel or gutter
formed at the junction of a pitched roof and
abutment wall, or behind a parapet or chimney to
convey water away.
!56
background see plastering background.
background noise, ambient sound; in acoustics,
general noise present in an environment.
background noise level in acoustics, the level of
background noise in a space.
back hearth the lowest masonry construction on
which combustion takes place beneath a flue in a
fireplace or fireplace recess; the floor of an open
fireplace.!55
backing1a structural base such as concrete, masonry
or a framework onto which cladding is fixed.
2 see back-up material.
backing coat see plaster undercoat.
backing strip see back-up material.
backings see plastering background.
backland open or bounded land to the rear of
existing buildings as viewed from a road or street.
backnut1a nut at a threaded pipework joint which is
tightened to secure the joint between two fittings.
2 see stop nut.
backplane see motherboard.
back-pressure valve see backflow valve.
back putty, bed putty; in glazing, a fillet of putty
applied to a rebate in a window frame, against
which a pane is bedded.
backsaw a handsaw with a rectangular blade whose
back is reinforced with a metal strip to inhibit bending;
used for carpenter’s benchwork.
backset the horizontal distance from the face of the
forend of a lock to the centre of the keyhole.
backsiphonage backflow of a liquid in pipework
caused by siphonage; see also backflow.
back-siphonage preventer see backflow valve.
back sliced veneer decorative veneer sliced from
the heart side of a half log or flitch.!10
Backsteingotik see brick Gothic.
back-to-back housing a form of basic urban
housing in Britain from the late 1800s and early
1900s consisting of rows of terraced or attached
houses constructed with frontages to streets in
opposite directions and sharing common party
walls on either side and to the rear.
!61
backtowall pertaining to a soil appliance such as a
bidet or WC which is connected to a wall or vertical
surface, through which all pipes, drains and outlets
etc. are connected.
backup a failsafe copy of a file or program.
back-up material, backer, backing; material such
as foam rubber strip placed into a construction
joint to limit the depth of overlaid sealant.!53
backwater valve see backflow valve.
back yard an enclosed yard or garden to the rear of
a building as viewed from the street.
badia an Italian abbey, a monastery or monastic
church headed by an abbot.
baffle a strip of material applied into construction
joints between components or materials as
weather or soundproofing.
bagasse board a building board manufactured
from the waste fibres from sugar cane processing.
baguette moulding see astragal.!14
Bahia rosewood [Dalbergia nigra] a Brazilian tropical
hardwood with yellowish brown streaked timber;
used in veneers and for interiors.
bail 1 see shackle.!39
2 see bailey.!103
bailey, 1 bailey wall; the fortified outer wall of a
castle, its first line of defence; often known as a
curtain wall.
!103
2 ward; the open area of land, yard or court
enclosed by a castle fortification wall, between the
keep and curtain wall.
!103
bail and bayle (trad.) are synonymous with both
meanings of bailey.
3 see enceinte.!103
4 see curtain wall.!103
Bailey bridge a prefabricated trussed steel bridge
used by the military and constructed in small sections
to allow for speedy assembly and dismantling
y closing off the front and sides
of a balcony above its balustrade.!54
balcony outlet, balcony drain; afittinginan
exposed balcony through which rainwater and melted
snow from a balcony floor or deck is conveyed to a
downpipe or other drainage system.
!54
balcony slab the structural concrete or stone floor
of a balcony.
!54
baldacchino see baldachin.!112
baldachin, baldacchino, baldaquin; anornamental
canopy of or representing fabric over an altar, throne,
bed or doorway; see ciborium.!112
baldachin altar a church altar situated beneath a
highly ornate canopy supported by columns, an
altar type typical in Baroque church architecture,
see also ciborium altar.
baldaquin see baldachin.!112
balection moulding see bolection moulding.
balineum Lat.; see balneum.!88
balistraria a narrow cross-shaped opening in the
external wall of a castle or fortification for crossbow
archers (balisters) to fire arrows at potential attackers;
also known as an arbalestina; see also arrow loop.
!103
balk see baulk.!2
Balkanization in town planning, the natural
fragmentation of groups according to social,
religious or ethnic background, forming areas
of distinctive quality and often interrelated
conflicts.
ball and flower, ballflower; an ovular decorative
motif found in the church architecture of the early
1300s, a stylized three-petalled flower enclosing a
small globule.
!123
ballast 1 material such as gravel, concrete slabs or
cast concrete laid above an insulating layer on roofs
and walkways to provide weight and prevent its
removal and deterioration by the forces of weather
and wind.
2 an electronic component for maintaining
a constant current applied to a discharge or
fluorescent lamp.
ball-bearing a construction or component consisting
of a number of steel spheres arranged in a ring and
cased, providing a frictionless support for a rotating
attachment.!38
ball-bearing butt hinge see ball-bearing hinge.
!38
ball-bearing hinge, ball-bearing butt hinge; a
hinge with a ball-bearing incorporated between
adjacent knuckles to reduce friction between
them.!38
ball catch, bullet catch; a catch which holds a door
closed by means of a sprung ball in a casing, fixed into
the edge of the door leaf; see also roller catch.
!39
ball clay a fine textured, plastic, adhesive natural
clay used in the manufacture of earthenware and
firebricks.
ballcock see ballvalve.
ballflower see ball and flower.!123
ball hinge a hinge whose pins rotate upon a
ball-bearing to reduce friction in turning.!38
ballium 1 Lat.; the enclosed courtyard of a medieval
castle; a bailey.
2 see bailey.!103
balloon see wire balloon.
balloon frame a form of timber frame construction
in which vertical studs rise from sole plate to
header plate through two or more stories;
intermediate floors are carried on wall plates nailed
to the inside face of the studs.!57
ball peen hammer a hammer whose peen is hemispherical.!40
ball pen, ball point pen; an ink pen having a small
metal ball at its point, which regulates the flow of
ink through rolled contact with the paper or base.
ball point pen see ball pen.
ballroom a large main hall in a mansion, institute
or public building, often used for celebratory
functions, especially dances.
ballvalve, 1 ballcock, floatvalve, float operated
valve; a valve in the flushing cistern of a soil
appliance which controls the level of water therein
with the aid of a float; a flushing valve.
2 in plumbing pipework, a valve containing a perforated
ball, which can be turned to align with
ports in the casing and allow liquid to pass through.
balm see balsam.
balneolum Lat.; see balneum.
balneum, 1 balineum (Lat.), balneolum, balaneion
(Gk); Lat., plural balneae; in Roman architecture, a
small public or private bath house, suite of rooms
etc.; see also thermae.!88
2 a bathing pool in a Roman bath house or dwelling.!91
balsam a fragrant and medicinal resinous exudation
from certain conifers; see oleoresin.
balsam fir [Abies balsamea] a Canadian softwood
whose cream-coloured timber is used for construction
work and packaging.
balsam poplar [Populus balsamifera, Populus
tacamahaca] a North American hardwood with
pale brown timber; used in
and electronics, a range of
frequencies between two defined limits.
2 see moulding.
band and hook hinge see hook and band hinge.
!38
bandcourse, string course; in masonry, a projecting
course, decorative moulding, row of bricks etc. set
into an elevation, often at storey level, to throw off
rainwater and as decoration.
see Pompeian styles illustration.!126
banded column 1 see annulated column.!114
2 see rusticated column.!13,!114
banderole, bannerol; in architectural decoration
and ornament, the depiction of an inscribed banner
or scroll.!123
banding 1 in decorative veneerwork and similar
crafts, strips of material arranged around central
panels to form a border.
2 a horizontal protrusion round the circumference
of the shaft of a column.!114
bandsaw a mechanical saw whose blade is a
toothed steel belt which revolves between two
powered wheels.
bandsawing the longitudinal sawing of timber with
a bandsaw.
bandsawn a description of timber which has been
resawn with a bandsaw.
bandstand a raised structure, often covered and
located in a park, upon which an orchestra or
band can play.
banister 1a light balustrade for a stair comprising a
handrail supported on closely spaced balusters.
2 one of the balusters in such a stair balustrade.
bank 1 a building or establishment for financial
transactions and various dealings in money.
2 see embankment.!31
banker 1 a timber workbench on which traditional
stonework is carried out.
2 a rough box, platform or bench in which small
batches of concrete, plaster or mortar are mixed by
hand.
banking 1a sloping mass of earth, an embankment.
2 see superelevation.
bankruptcy a financial situation in which a
company is unable to pay its debts, and whose
assets are seized and distributed to benefit its
creditors.
bank seat in bridge construction, a foundation at a
bridge abutment.
bank transfer, transfer; a document authorizing
the transfer of funds from an account.
bannerol see banderole.!123
banqueting hall 1a large main hall in a mansion,
institute or public building, often used for celebratory
functions, especially dinners.
2 see estiatorion.
!92
banquette a raised step or platform along the inside of
arampartofacastleorfortification,fromwhichdefending
soldiers may give fire over a high parapet.!103
baptismal font see font.
baptistery, baptistry; a space, area or separate
building of a church or cathedral, containing a
font where baptism takes place.
see Byzantine domical church illustration.!96
see Carolingian abbey church illustration.!98
see Romanesque church illustration.!99
baptistry see baptistery.!96,!98,!99
bar 1 any longitudinal solid length of material with a
uniform cross-section, usually metal; called a section
when thin flanged or hollow; types included as
separate entries are listed below.
see metal bars illustration.!34
angle bar, see steel angle.
crow bar.
deformed bar.
flat bar, see flat.
!34
glazing bar.
!111
hexagonal bar.
!34
locking bar.
panic bar.
reinforcing bar.!27
round bar.!34
square bar.!34
T-bar, see T-section.!34
threaded bar, see threaded rod.!36
water bar.
2 in heraldry, a narrow fess.!125
3 a small establishment where drinks are sold, see
public house.
4 the counter in a bar or restaurant, from which
food and drinks may be served.
barbacan see barbican.
barbe see barbette.!103
barbecue, grill; an outdoor fireplace on which food
may be cooked, often a metal grille placed over an
open fire or a proprietary apparatus fuelled by
charcoal.
barbed cross 1 see cross crampone´e.!118
2 see cross barbe´e.
!117
barbed moulding a decorative moulding with a
series of hooked motifs joined end on end; primarily
found in heraldic designs.
!125
barbedwire a steel wire product wound with a series
of sharp protrusions; used for security fencing.
obsolete, consisting of barium
chromate; used formerly in oil paints.
bark 1 the exterior protective layer of tissue on a
tree.!1
2 see birch bark.
bark beetle [Scotylidae] a family of insects which
damage hardwood trees and their unseasoned
timber by burrowing beneath the bark.
bark borer [Ernobius mollis] an insect whose larvae
burrow under the bark of dry softwood logs.
bark pocket see inbark.
bark-thatched roof a traditional roof in colder
climates, whose waterproof consists of overlapping
strips of bark peeled from birch or other trees, laid
as tiles and often covered with boards or turf.!48
bark-ringed knot see encased knot.!1
barking chisel, peeling chisel, peeling iron; a
wide-bladed chisel or similar implement for peeling
or stripping bark from boles.
barley-sugar column see spiral column.!114
barmkin, barbkin; a fortified enclosure round a
Scottish castle or tower house for the protection
of livestock; in Ireland it is known as a bawn.
barn,1 cowshed; an agricultural outbuilding for the
housing of livestock, their feed etc.
2 a similar structure for the storage of grain, hay,
agricultural implements etc.
barometer an instrument for measuring the pressure
of surrounding air or that in the atmosphere.
barometric damper see draught diverter.
!56
barometricpressure, atmospheric pressure; the
pressure of the air in the atmosphere.
baronial style a romantic architectural style in Great
Britain from the 1800s and early 1900s characterized
by medieval motifs such as turrets and gatehouses,
and used mainly for private castles, country houses,
hotels and other buildings of significance; see also
Scottish baronial.
Baroque an architectural style originating from
southern Europe in the 1600s and 1700s,
characterized by classical motifs used in a dramatic
and theatrical manner, lavish ornamentation and
integration of art and sculpture; phases of Baroque
architecture included as separate entries are listed
below.
see Baroque window illustration.!111
see Baroque portal illustration.!113
see column styles in European architecture
illustration.!114
early Baroque.
high Baroque.
late Baroque.
Baroque classicism see Louis XIV style.
barque sanctuary a room or building within an
ancient Egyptian temple complex in which the
solar barque of the Pharaoh or deity, or its image,
was revered.!72
barquette ‘tray’ Fr.; see barbette.!103
barrack 1 temporary accommodation or a hut for
workmen, soldiers etc.; often used in the plural.
2 soldiers’ communal accommodation; also known
as a billet.!104
barred window a window with a protective or
security grille affixed over its exterior face.
barrel a unit of capacity of both wet and dry goods,
especially oil and foodstuffs: for oil and associated
products this has been fixed by standard at 35
imperial gallons, 42 US gallons or approximately
159 I.
barrel bolt 1 a simple fastener for a door or gate
consisting of a round metal bar which moves in a
tube or ring, fixed to the door, and engages in a
hole in a jamb or gate post.!39
2 see foot bolt.
!39
3 see flush slide.
barrelnipple, shoulder fitting (Am.); in pipework,
a short connecting pipe which is externally
threaded at either end, and which often has a cast
nut in between for tightening with a spanner.
barrel vault, 1 cradle vault, cylindrical vault,
tunnel vault, wagon vault, wagonhead vault;
a masonry or concrete roof vault which is
semicircular in cross-section, especially used in
early churches.!25
2 see pointed barrel vault.!25
barrel vaulted roof any roof structure which is
semicircular in section and in the shape of an
elongated semicircular arch.
barrier a physical obstacle, rail etc. designed to
prevent access or penetration; types included as
separate entries are listed below.
access barrier, see vehicular barrier.
boom.!64
cavity barrier, see fire barrier.
crash barrier, see vehicle safety barrier.
fire barrier.
noise barrier.
plenum barrier.
safety barrier, see vehicle safety barrier.
snow barrier.
traffic barrier, see vehicular barrier.
vapour barrier.
!8
vehicle safety barrier.
vehicular barrier
ustration.!76
2 see classical base.!76,!78,!81
see column base in classical orders illustrations.!78,
!79,!80
see column styles in European architecture
illustration.
!114
see Asian and Mediterranean columns and capitals
illustration.
!69
3 a substance which may chemically combine with
an acid to form a salt.
4 see substrate.
!20
5 the lower portion or lower third part of a heraldic
shield.!124
baseboard 1 see skirting board.!2,!44
2 see gypsum baseboard.
base coat, 1 brown coat, browning coat, floating
coat, key coat; in plastering and rendering, a
roughly finished layer or layers of mortar applied to
masonry to provide a key or even surface for a
finish coat.!83
2 see base coat in Roman walling illustration.!83
base course, 1 roadbase; in road construction, a
surfacing layer of material directly beneath and
supporting the wearing course.!62
2 the lowest course of stones, bricks or blocks in
masonry walling.
3thelowestlayeroflogsinhorizontallogconstruction.
base cruck truss in traditional timber frame
construction, a simple principal truss of curved
timber members or crucks which meet at a
collar, supporting the purlins onto which rafters
are laid.
base floor, bottom floor; the lowest constructed
floor level of a building, that adjacent to the
ground; it may be at basement or ground floor
level.!28
base floor construction the horizontal layers of
construction which make up a base or bottom
floor.!59
see base floor construction in brick house
illustration.!59
basement the usable area of a building that is
situated partly or entirely below ground level and
may contain habitable rooms; in North America it is
less than halfway below ground level.!61
basementarea, dry area, area; in town houses, an
unroofed narrow external space below street level
to provide light, air and often access to rooms in a
basement, and to separate external basement walls
from the surrounding ground to prevent entry of
water.
basement floor see basement storey.!61
basement parking an area of parking located in
the basement of a building.
!62
basementstorey, basement floor; a storey below
the ground floor of a building, which may contain
habitable rooms, utility or storage spaces.!61
base moulding a decorative moulding at the lower
end of the shaft of a column.!80
base plate see sole plate.!8,!57,!58
base ring, base unit; in drainage, a suitably shaped
precast concrete, ceramic or plastics component
used as the base for an inspection chamber or
well, around which it is constructed.
base rock see bedrock.
base sheet, 1 reference drawing, underlay; a
drawing or graphic image whose information is
used, often by tracing through, in the production
of a drawing.
2 first layer felt; in built-up roofing, the lowest
layer of bitumen felt, often bonded to the
underlying structure and intermediate sheet above.
base unit see base unit.
base wall see wall base.
see Roman walling illustration.
!83
see concrete frame illustration.
!28
see timber-framed building illustration.
!57
basiclead carbonate a form of the pigment white
lead.
basic rock types of igneous rock whose silica
content is between 45% and 52%.
basic wage the normal amount paid to an
employee on a regular basis, before the inclusion
of deductions, bonuses or additional payments.
basilica 1 a Roman building type, rectangular in
shape with an apse at either end, used as a court
of justice and an exchange.!93
see Roman basilica illustration.!93
2 a building type consisting of a clerestoried nave,
side aisles and terminated with a rounded apse
containing an altar; adopted by the Early Christian
church from Greek and Roman precedents.
see Early Christian basilica illustration.!95
3 see basilica church.!99
basilica church a church type based on a basilica
antecedent, usually with a rectangular plan divided
by colonnades into a nave and aisles, with an apse
or apses at one end.
!99
see basilica church in Romanesque church
illustration.
!99
basilica discoperta a basilica chu
ght as the curtain wall which
joined them.
bastille house see bastle house.
bastion a polygonal structure projecting from the main
fortified wall of a town or castle,withtwo ormore long
faces meeting at an angle, used for siting cannon and
otherweaponrytoaffordclearfireinanumberofdirectionsoutsidethemainlineofdefence;typesincludedas
separateentriesarelistedbelow.
!103,!104
arrow-headed bastion.
!104
demi-bastion.
!104
double bastion, see cavalier.!104
half bastion, see demi-bastion.!104
inner bastion, see cavalier.!104
bastioned trace see bastion trace.!104
bastion face see face.!104
bastion flank see flank.!104
bastion front see bastion trace.!104
bastion line see bastion trace.!104
bastiontrace a fortified front consisting of a number
of bastions connected by a curtain wall; a polygonal
fortification, also called a bastion front, bastion line
or bastioned trace.!104
bastle house, bastel house, bastille house; a
traditional dwelling from the border area of
England and Scotland, whose lowest storey is
fortified against assault.
bat, 1 brickbat; a full brick cut down to size in order
to act as a space filler in bonded brickwork; often
larger than a quarter brick; types included as
separate entries are listed below.
!21
halved three quarter bat.
!21
half bat.
!21
quarter bat.
three quarter bat.
!21
2 mineral wool and other insulating products
manufactured into thick slabs for ease of storage
and installation.!59
batardeau a wall built across a fortification ditch or
moat to regulate the amount of water therein,
constructed with a sharp ridge to prevent its use
by attacking troops.
batch1a portion of material or goods mixed for use,
packed for delivery etc. at any particular time.
2 see concrete batch.
3 see plaster batch.
batch mixer in the production of concrete, a mixer
which produces a set amount of concrete at any
one time; see also continuous mixer.
batch production the manufacturing or processing
of a product or material in a series of predetermined
quantity rather than in a continuous run.
batching see proportioning.
batching and mixing plant see batching plant.
batching plant, batching and mixing plant; an
industrial assembly for mixing concrete to be used
on site.
bath, bathtub; a large vessel connected to a water
supply and a drain, in which a person can be fully
immersed in water while washing; types included
as separate entries are listed below.
footbath.
hip bath.
jacuzzi.
plunge bath.
treatment bath.
whirlpool bath.
bath house 1a public or private establishment for
personal cleaning, swimming and relaxation.
2 see thermae.!91
3 see balneum.!88
bathroom 1a room for personal cleaning, containing
a bath or shower and other sanitary appliances.
!57,!59
2 see balneum.
!88
bathroom lock a lock designed for use principally
with the doors of bathrooms, toilet cubicles etc.,
containing a latch with handles, and a dead bolt
operable from the inside only; the dead bolt is
connected to an indicator panel to show whether
the room is occupied or not.!39
baths 1 a public or private establishment for personal
cleaning, swimming and relaxation.
2 see thermae.!91,!94
3 see balneum.!88
4 see loutron.!91
bathtub 1 see bath.
2 see loutron.!91
batik an originally Malayan method of making
graphic prints on cloth by masking patterned
areas with wax; the dyed cloth is then boiled to
melt the wax, leaving a design of undyed marks.
bat’s wing an arched decorative motif with lines or
flutes radiating from a central point, resembling the
outstretched wings of a bat.!123
batted finish, broad tooled finish; a stonework
finish with a series of parallel cut grooves produced
by dressing with a batting tool.
!12
batten 1 one of a number of strips of timber laid at
regular spacing as a base onto which cladding,
sheet materials and tiles may be fixed; types
included as separate entries are listed below.
!57
counterbatten.
flooring batten.!
tool; a broad-faced masonry
chisel used for dressing stone with a batted or
fluted finish.
!41
battlement, embattlement; a crenellated parapet
and walkway in a castle or fortified wall, used for
the purposes of defence; see also crenellation.!103
see battlement illustration.!103
battlemented see castellated.
battlemented moulding see crenellated moulding.!124,!125
Battle of the Styles a period in English architectural
development from the mid-1800s centring on which
revival style, especially Gothic and classical, was
suitable for use in public buildings.
baud in computing and telecommunications, a unit
of transmission speed equal to one information
unit or bit per second.
Bauhaus a school and movement in modernist architecture,
design and craft founded by Walter Gropius in
Weimar in 1919, which functioned until 1933 in Dessau.
bauk see baulk.!2
baulk a piece of sawn timber with cross-sectional
dimensions of 100 mm100 mm or larger; in
traditional timber construction, it may be a squared
log; any heavy log or timber; also variously written
as bauk, balk or bawk.
!2
bauxite a white or reddish sedimentary rock, a dense
and earthy clayish mineral which contains a high
proportion of aluminium and is thus used as its
principal ore.
bawk see baulk.!2
bawn see barmkin.
bay, 1 trave; a division in a ceiling or roof marked
out by adjacent vaults, beams or arches, especially
in stone vaulted architecture.!25,!101
2 the division of a space defined by the spacing of
roof trusses, partitions or columns.
3 an area of natural water, sea or a lake surrounded
by land on three sides.
4 see loading bay.
5 see parking space.
6 see bus bay.
bayle see bailey.!103
bay-leaf garland an ornamental motif found in
classical and Renaissance architecture consisting of
a mesh of lines which intertwine to form openings in
the shape of eyes or bay-leaves.
!82
bayonet cap a lamp cap which connects to a holder
by means of transverse pins in its side.
bayonet saw see jigsaw.
bay window a window set into a protrusion from
the elevational plane of a building.
bazaar an oriental covered market or arcade of
shops.
beach an area of coast or shoreline, often with sand
or shingle, used for recreation, swimming and
sunbathing.
beaching small stones of 70 mm–200 mm used as
revetment for embankments.
bead, 1 beading; a thin strip of planed timber or other
material used for covering joints, fixing of glazing or
panelling in frames and as surface decoration.
see timber trim illustration.!2
2 see glazing bead.!2,!53
3 see bead moulding.
4 see beaded moulding.
bead and quirk moulding see quirk bead moulding.
!14
bead and reel, reel and bead; a decorative
moulding consisting of a series of small round
beads, elongated hemispheres or half-cylinders
alternating with pairs of flattened discs.!80,!82,
!124
bead boarding decorative timber cladding boards
whose surface is planed with a series of convex
mouldings or reeds: also called reeded or moulded
boarding.
!8
bead saw a small fine-toothed saw, 100 mm–250 mm
long, with a reinforced back and turned handle, used
for fine work.
beaded joint a brickwork mortar joint in which the
mortar is laid flush with the brick surface then
scored with a special tool to form an inset convex
shape or bead.!16
beaded moulding, 1 paternoster, pearl
moulding; an ornamental motif or moulding
consisting of a row of beads or small hemispheres;
also loosely known as a bead moulding.!124
2 see bead and reel.!80,!82
bead edged boarding decorative timber cladding
boards whose edge has been planed with a bead.!8
beading see bead.
bead moulding, 1 roundel; a slender decorative
moulding, semicircular in cross-section; when
found in classical architecture it is called an astragal.
!14,!126
2 see beaded moulding.!124
3 see pellet moulding.
!124
bead polystyrene see expanded polystyrene.
beakhead see beak moulding.!122
beak moulding, 1 beakhead; a decorative
moulding of Norman origin formed with pointed
projections resembling the head of a man, bird or
mythical beast with a protruding beak or lip.!
beam.
principal beam, primary beam.
ridge beam.!33
rood beam.
roof beam.
!48,!59
secondary beam.
solid timber beam.
!7
spine beam, see mono-carriage.
!45
steel beam.
stiffening beam.
!32
straining beam.!33
strut beam, see collar beam.!33
summer beam, see summer.
T-beam, tee beam.!30
tie beam.!33
timber beam.
trabs, trabes.!47
transverse beam, see cross beam.
trimmed beam.!4
trimmer beam, see trimmer.!4
trussed beam.!33
universal beam, see I-section.!34
upstand beam.
wind beam, see collar beam.!33
2 a narrow ray of light or other radiation.
beam block bond-beam block, see channel block.!30
beam box, beam form; formwork for a reinforced
concrete beam.
beam brick see lintel brick.
!16
beam bridge see continuous beam bridge.!32
beam compass, trammel; a compass for the
drawing and marking out of large circles, whose
centre pin and scribing device are along the length
of a rod or beam.
beam form see beam box.
beam reinforcement steel reinforcement for a
reinforced concrete beam.!27
beam spread in artificial lighting, the angle over
which a spotlight or floodlight directs the major
quantity of its light output.
beam unit see precast beam.!28
beam vibrator in the compaction of fresh concrete,
a surface vibrator in the shape of a beam.
bearer any device or construction for holding a
component in place.
see ceiling bearer.!60
see gutter bearer.!46
see soffit bearer.
bearing a structural device which transfers load from
a moving, movable, slipping or rotating part to a
fixed support.
see ball-bearing.!38
see bridge bearing.
see roller bearing.
see sliding bearing.
bearing capacity, loadbearing capacity, loading
capacity; the amount of force, pressure, weight or
stress that a material, soil, foundations or a structure
can safely withstand without failure.
bearing pile, foundation pile; in foundation
technology, a pile which transmits vertical rather
than earth-pressure loads to the ground or hard
subsoil.!29
see types of pile in foundation drawing, and list of
common pile types under ‘pile’.!29
bearing seat see bridge cap.!31
bearing surface any surface which bears the thrust
of a structural component.
bearing wall see loadbearing wall.!28
bearing wall system see loadbearing wall construction.!28
beast column see animal column.!114
beauty parlour commercial premises for preserving
or improving the aesthetic value of the face or
body.
Beaux Arts an architectural style originating from
France at the e´cole de Beaux Arts in the 1800s,
characterized by monumental forms and eclectic
decoration.
beaver a shade of dark brown which takes its name
from the colour of the pelt of the beaver (Castor
fiber).
becquerel Bq the SI unit of radioactivity, equal to
one disintegration per second.
bed 1 the lower horizontal surface of a brick as laid in
masonry.
!21
2 bedding; a layer of material, often mortar, in
which a brick, block or stone is laid.
3 bedding; the horizontal joint thus formed; a bed
joint.
4 floor bed, see ground supported floor.
5 the lower surface of a roofing slate.
6 stratum; in geology, a layer of sedimentary rock
and the natural plane in which it lies in the ground.
7 a piece of furniture designed for sleeping
etimes also called a studio
apartment.
bedstone, foundation stone; a large flat boulder
used as a foundation, usually for a temporary or
traditional timber building.
!6
beech [Fagus spp.] a group of hardwoods from
Europe, Asia Minor, Japan and North America
whose heavy, strong, hard, tough, pale pink timber
has flecked markings; used for flooring, interiors
and furniture; seeFagusspp. for full list of beech
included in this work.
beehive cell, clochan; an Early Christian drystone
dwelling used by monks in Ireland and the Scottish
Western Isles, constructed in the shape of a beehive
with corbelled vaulting.
beehive tomb see tholos.!65
beeswax wax produced by bees, applied with a
solvent to finished joinery and polished as a surface
treatment.
beetle, 1 maul; a sledgehammer with a wooden
head, used for driving in pegs, wedges and staves.
2 any hard-shelled insects of the order Coleoptera,
many of which cause damage to trees, timber,
and timberwork in buildings; species included as
separate entries are listed below.
ambrosia beetle, [Scotylidae, Platypodidae].
bark beetle, [Scotylidae].
common furniture beetle, [Anobium punctatum].
death-watch beetle, [Xestobium rufovillosum].
furniture beetle.
house longhorn beetle, [Hylotrupes bajulus].
longhorn beetle, [Cerambycidae].
lymexylid beetle.
sawyer beetle, [Monochamus].
spruce beetle, [Tetropium spp.].
woodworm, see furniture beetle.
3 dung-beetle ornament; see scarab.!75
see Khepri.!75
beetroot purple a shade of purple which takes its
name from the colour of the root of the beetroot
(Beta vulgaris).
beige, ecru, flaxen, light blonde; a general name
for shades of greyish yellow similar to the colour of
unbleached and uncoloured wool, and the colour
of the ripened flax plant.
Belfasttruss a roof truss composed of a curved upper
chord and flat lower chord braced by diagonals; a
bowstring truss.!33
belfry, belltower; a structure for housing bells,
surmounting the roof of a church or cathedral, or
freestanding.
see belfry in Scandinavian hall church illustration.!102
Belgian truss see fink truss.!33
bell1 the bulging part of a hammerhead which bears
the striking face, opposite the peen.
!40
2 see socket.
3 see church bell.
4 see doorbell.!51
5 see campanula.!78
6 see calathus.!81
bell-and-spigot joint see spigot-and-socket joint.
bell arch 1a round arch supported on corbels with
rounded undersides, often in a different stone.!23
2 see reverse ogee arch.!24
bell capital, 1 blossom capital, campaniform,
open capital; an Egyptian capital carved in the
form of an upside-down bell in stylized imitation of
an open papyrus or lotus flower.!73
see papyrus capital.!73
2a medieval capital type with a central conical drum
terminated at upper and lower edges by rings, discs
or annulets.!115
3 see trumpet capital.!115
bell cast in renderwork, the thickening of the lower
edge of a laid render coat to act as a drip.
bellcot see bellcote.
bellcote, bellcot, bell gable; a small belfry which
surmounts the ridge of the roof of a church or
public building.
belled pile see under-reamed pile.!29
bell face hammer a hammer whose striking face is
rounded so as to avoid damaging the surrounding
surface when driving nails.!40
bell gable see bellcote.
bell pavilion a structure housing a large bell, used
in ritual cleansing ceremonies in Japanese Buddhist
and Shinto temples.!68
bell pliers large pliers with notched jaws, side cutters
and a notched depression; used for gripping and
cutting wire.
belltower a church or other tower containing bells
in an open or louvred chamber near the top; see
belfry.
see Early Christian church illustration.!95
see Byzantine domical church illustration.!96
see campanile.!96
belt a longitudinal area of landscaped greenery;
greenbelt.
see balteus.
!90
belt conveyor mesh see conveyor belt mesh.!34
belt sander a hand-held power sanding tool
with a motor-driven belt of sandpaper or abrasive
cloth.
beltway see ring road.