Davies Nikolas - Dictionary of Architecture and Building Construction

A0 a standard international paper size of 841 mm 1189 mm (33 46), whose measurements are derived from its area (1 m2) and the ratio of the lengths of its sides (1:2); smaller derivative sizes A1A10 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

Aarons 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 0C kelvin or 273.16C.

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.

absorption 1 a 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 non-representational 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, Bears breech or brank-ursine [ 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.

accent lighting 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 contractors 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.