SAH Archipedia uses terms from the Getty Art and Architecture Thesaurus (AAT) to categorize and classify metadata for the entries in the database. For more information on the Getty AAT, click here

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abalone shell

Bowl-like shells of the abalone mollusk, a source of mother of pearl.

Acer (genus)

Genus containing around 200 species of shrubs or trees widely distributed in the North Temperate Zone, but concentrated in China. Maples are used as ornamentals, tapped for syrup, and provide valuable, dense hardwood for furniture and other uses. All maples bear pairs of winged seeds, called samaras or keys. The leaves are arranged oppositely on twigs. Many maples have lobed leaves, but a few have leaves separated into leaflets. More recent classifications place the genus in the family Sapindaceae, although some have placed it in a family of its own, Aceraceae.

Acer palmatum (species)

Species of deciduous shrub or small tree native to Japan, North Korea, South Korea, China, Mongolia, and southeast Russia; reaching 10 meters in height and typically an understory plant in shady woodlands. The tree may have multiple trunks joining close to the ground. Many different cultivars of this maple have been developed; even in the wild, seedlings from the same parent display remarkable variation in color and shape of leaves.


Nut of oak trees and shrubs, growing in a shallow woody cup or cupule.

acoustical plaster

Finishing plaster designed to correct sound reverberations or reduce noise intensity.

acoustical tile

Any tile composed of materials having the property of absorbing sound waves.

acrylic (plastic)

Colorless, transparent, thermoplastic synthetic resin made by the polymerization of acrylic acid derivatives; used for adhesives, fibers, consolidants, protective coatings, finishes, and as a paint medium.

adobe (material)

Handmade, sun-dried brick typically made from wet mud and straw, sometimes also containing sand, clay, dung, grass, chaff, or blood. It is porous, wettable, susceptible to wet-dry cycle degradation, but good heat insulation. Adobe walls are typically built using mud mortar between the brick layers followed with a mud stucco finish layer. It was used as early as 7000 BCE for houses, buildings, and pyramids, particularly in arid climates such as Mesopotamia, Persia, Palestine, India, China, and the pre-Columbian Americas. For sun-dried brick that may or may contain the binders of adobe, use the more general "sun-dried brick."

African mahogany (wood)

Wood of trees belonging to the genus Khaya, native to Africa. It has a pink heartwood when freshly sawn, which darkens to a pinkish-brown to a deep red. It closely resembles true mahogany. It is used for making cabinets, musical instruments, veneer, furniture, boat planking and cabins, banisters, and handrails.

agate (chalcedony)

Cryptocrystalline chalcedony, showing a variegated banded structure and waxy luster. Agate bands are caused by the deposition of successive mineral layers from solution and may be either straight, wavy, or concentric. Agate is slightly harder than quartz. It has been gathered or mined since Neolithic times. It may distinguished from onyx by the parallel structure of the bars in onyx.


Inert granular material such as natural sand, manufactured sand, or gravel that, when bound into a conglomerate mass, forms concrete or mortar.

air-dried lumber

Lumber that has been dried by exposure to air in a yard or shed, without artificial heat

air-entrained concrete

Concrete containing minute air bubbles that improve its workability and frost resistance.

Alabama Cream

An American white marble suitable for sculpture.

Alabama limestone

A light tan-gray or nearly white oolitic limestone quarried in Colbert County, Alabama that contains large isolated shells and other fossils.

alabaster (mineral)

Fine-grained marblelike variety of gypsum that is easy to carve but is rather fragile; it has been used as a sculpture material, ornamental building work, vases, small decorative carvings, and powdered for use as a paper filler and paint pigment called mineral white or terra alba. Alabaster is usually a translucent white or pink but may also be a muted red, yellow or gray. It is soft and can be scratched slightly with a fingernail. It also dissolves slowly in wet environments.

Alberene stone

A bluish gray stone quarried in Virginia; commonly used for building trim and for chemical laboratory tables and sinks; hard varieties employed for stair treads and flooring.

Albizia (genus)

Genus containing around 150 species of flowering trees, shrubs, and lianas of tropical and subtropical regions, some of which are cultivated as ornamentals or for their timber. The genus was named after Filippo del Albizzi, a Florentine nobleman who in 1749 introduced A. julibrissin into cultivation.

alloy steel

A general name for steel that owes its distinctive properties to elements other than carbon; types of alloy steel typically take the name of the element or elements that are most influential on their character. Usually used for toolmaking and building.


Colorless-to-white crystalline potassium aluminum sulfate; has a wide range of uses, including in treatment of leather and textile, in sizing paper, as a mordant in dyeing, and as a water-purifying agent.

aluminum (metal)

Pure metallic element having symbol Al and atomic number 13; a hard, strong, silver white metal. This metal is also processed and formed, usually in combination with other substances, to make objects and materials.

aluminum alloy

When not further qualified, the term refers to aluminum-copper alloy with or without small amounts of other alloying elements. Due to the influence of even tiny amounts of other elements on aluminum, there is an infinite variety of aluminum alloys.

aluminum cans

Cans made of aluminum.

aluminum paper

Paper of silvery appearance coated with powdered aluminum.

American chestnut (wood)

Wood of the species Castanea dentata; it is similar to oak with a light brown, coarse grain. The durable wood was widely used prior to World War II for paneling, framing, fence posts, rails, shingles, office desks, and coffins. Trees are have a limited range today; while formerly found throughout North America, they were largely killed off by a fungus in the 20th century.

American elm (wood)

Fine-grain, durable wood of the species Ulmus americana, used chiefly for ship building, ax handles, or other uses requiring a combination of strength, bending qualities, and ability to withstand rough usage.

American linden (wood)

Wood of the species Tilia americana of the eastern United States and Canada. It varies in color from creamy-white to almost brown, and is used in the manufacture of constructional veneer, plywood, piano actions, and turnery.

American sassafras (wood)

Wood of the species Sassafras albidum, native to eastern North America. It is soft, lightweight, and moderately coarse, used for fence posts and furniture.

American tulipwood (wood)

Soft, fine-grained wood of the species Liriodendron tulipifera of North America. The sapwood is usually a creamy off-white color; heartwood is pale green, often with streaks of red, purple, or black. It is cheap, easy-to-work, can take a sharp edge, and is stable, used to seal pipes and valves in organs, for siding clapboards, coffin boxes, pattern timber, and wooden ware.

amethyst (mineral)

Purple or bluish-violet varieties of quartz, that have gathered or mined since Neolithic times.

Amherst sandstone

A stone from Ohio, containing up to 95% silica with 4% aluminum oxide, and colored gray and buff with iron oxides.

angle brick

Any brick having an oblique shape to fit an oblique salient corner.

anhydrous gypsum plaster

Completely de-hydrated gypsum that is combined with an accelerator to abbreviate setting time. Due to it's hard surface, it is used as a final coating.

annuals (plants)

Designates plants that complete their cycle from seed to seed in a single year.


Non-bituminous and most highly metamorphosed form of coal containing more fixed carbon and least amount of volatile matter than any other form. Anthracite is the least plentiful form of coal.

aquamarine (mineral)

A transparent, light bluish green gem variety of beryl.

Aquia Creek sandstone

A brown to light-gray siliceous sandstone from Aquia Creek in Stafford County, Virginia. It contains rounded, coarse to fine grains of quartz as well as scattered pebbles and clay pellets as big as 1 inch in diameter; it splits easily in any desired direction. Aquia Creek sandstone was one of the important building stones in early Washington, D.C.

architectural bronze

Bronze of very high copper content, formulated for color.

architectural glass

Flat glass used for utilitarian purposes, although the term is sometimes used to describe what is known as stained glass. In modern times some is made in solid or hollow blocks to be used for building walls. Can be decorated by etching, sandblasting or other techniques.

architectural mirrors

Mirrors contained in frames that have strong architectural features, often including side columns and pediments.

architectural terracotta

A hard-burnt, glazed or unglazed clay unit used in building construction, machine extruded or handmade.

Arecaceae (family)

Family of flowering plants containing nearly 2,400 species of palms in 189 genera.

Arizona flagstone

A fine grained ferruginous sandstone quarried in Arizona that can be buff, brown, or pink in color; it is one of the most common and inexpensive sedimentary stones used as flagstone. It is strong, abrasion resistant, and has a natural non-slip surface, making it an exceptional flooring material. It is colorfast and can be used indoors or outdoors.

Arnaudon's green

An obsolete variety of hydrated chromic phosphate; it is the hemiheptahydrate form of chromic phosphate, comprising a powder having a bluish green color and used as a paint pigment.

art glass (material)

Glass, especially types invented in the 19th century, that incorporated newly developed techniques for producing colors and surface textures.

art glass (ornamental visual works)

Glassware, particularly that dating to the mid- to late 19th century, that was made for ornamental more than for utilitarian purposes and that was made of material that incorporated newly developed techniques for producing colors and surface textures. For the general concept of works made of glass, use "glassware."

artificial asphalt

Asphalt mixture of 13-60 percent bitumens with finely pulverized mineral fillers, usually limestone. It differs from natural asphalt by the presence of paraffin and a greater content of petroleum oils.

artificial asphalt

Asphalt mixture of 13-60 percent bitumens with finely pulverized mineral fillers, usually limestone. It differs from natural asphalt by the presence of paraffin and a greater content of petroleum oils.

artificial stone

Any combination or mixture of materials made to imitate stone.


A commercial term for any of several fibrous magnesium silicate minerals readily separable into thin, strong fiber that is flexible, noncombustible, heat resistant, and chemically inert; used in a wide variety of industrial products. It was used by the ancient Greeks, Egyptians, and Chinese as a fireproof material. In the 19th and early 20th centuries, asbestos was used for fireproofing and insulating houses: small asbestos fibers were mixed with binders and compressed into boards, paper, pipe covering, ironing board covers, shingles, tiles, and sprayed onto ceilings. Long asbestos fibers were woven into fabrics for used in brake linings, heat-resistant shields, gloves, and fireproof garments and blankets. Health concerns have limited the use of asbestos since the early 1960s. In the U.S., it was declared a hazardous material in 1986.


Fire-resistant, waterproofing material made by combining portland cement with asbestos fiber.

ash (residue)

Earthy or mineral residue that remains after combustible substances have been thoroughly burned.

ash (wood)

Wood of any of several trees belonging to the genus Fraxinus, having distinctive growth rings with very large open pores beside small, tight pores. The wood is light in color, dense, elastic, and having a straight grain that is moderately durable but susceptible to insect attack and moisture degradation. The tough, heavy timber is used for ladders, tool handles, oars, poles, gymnasium equipment, and hockey sticks because it produces a smooth surface that rarely splinters. Ash was also popular for furniture (especially Colonial pieces), wheels, and carriage frames, and is used for decorative veneers.


Small dimension stone with a flat faced surface, usually square or rectangular.

ashlar brick

A brick whose face has been hacked to resemble roughly hacked stone.

asphalt (bituminous material)

The dark, brownish-black bituminous resin that is found in natural deposits or is produced as a byproduct of oil refineries. It has consistencies varying from viscous liquid to glassy solid. It is composed of aliphatic, alicyclic, and polycyclic aromatic hydrocarbons. It is soluble in oils and waxes and can act as a plasticizer or a strengthener, depending on the hardness of the variety. Natural asphalt, which is believed to have been formed during an early stage in the breakdown of organic marine deposits into petroleum, characteristically contains minerals, while residual petroleum asphalt does not. Asphalt has been used since the 3rd millennium BCE for waterproofing; it is also used for road paving, roof coating, joint sealing, and a waterproof barrier in sandy soils. Ancient sources for asphalt were Egypt, the north end of the Dead Sea, the Is river northwest of Babylon, and the Greek island of Zante.

asphalt cement

Adhesive and binding material that is a preparation of refined asphalt and heavy petroleum oil, made by refining petroleum until there is no water or foreign matter in it, except for the minerals naturally found in the asphalt. Asphalt cement contains less than one percent ash. Usually used for paving.

asphalt concrete

A composite material consisting of gravel, sand, and stone that is bound together with asphalt; it is laid down in layers and compacted. It is commonly used in construction projects such as road surfaces, airports, and parking lots. The ingredients are mixed under high temperatures and kept heated until applied to a surface.

asphalt shingle
No description is available for this term.


Rooms or entire buildings designed for a variety of activities such as would occur on a stage before a seated audience; for rooms or buildings used only for theatrical performances, use "theaters;" for rooms with fixed seating designed for lectures, use "lecture halls."


Roof-like coverings, usually of canvas or metal and often adjustable, placed over windows, doors, or decks to provide protection from sun and rain.


Earthenware tile of Spanish or Portuguese manufacture, painted and enameled in rich colors. They are typically large and used to decorate the exterior walls of buildings. The term is probably of Arabic origin but its derivation is debated.