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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gauged brick

Brick that has been ground or otherwise produced to accurate dimensions.

Georgia marble

Any of several coarse-grained, pale-colored marbles quarried in northern Georgia. White Georgia is used for statuary. The others, such as Georgia Cherokee and Silver Georgia gray, are used as interior and exterior building stones.


A white priming or ground made of chalk, gypsum, burnt gypsum, zinc oxide, or whiting mixed with glue or occasionally casein. Used to prepare wooden panels or other supports for painting, gilding, or other decorative processes.

gilding (material)

A thin layer of gold or other metal that has been applied as a decorative surface finish, whether the metal was applied as a thin leaf, by electroplating, or as a thin paint layer. Examples of gilding include that applications on paintings, furniture, frames, sculptures, and the edges of pages of books.

gilt paint

Paint having gold as a pigment, often in combination with another pigment of similar color.

No description is available for this term.

glass (material)

An amorphous, inorganic substance made by fusing silica (silicon dioxide) with a basic oxide; generally transparent but often translucent or opaque. Its characteristic properties are its hardness and rigidity at ordinary temperatures, its capacity for plastic working at elevated temperatures, and its resistance to weathering and to most chemicals except hydrofluoric acid. Used for both utilitarian and decorative purposes, it can be formed into various shapes, colored or decorated. Glass originated as a glaze in Mesopotamia in about 3500 BCE and the first objects made wholly of glass date to about 2500 BCE.

glass block

Material made from glass, having a three-dimensional rectangular form and used architectural building or decorative elements; its function is to admit light while providing visual obscuration.

glass curtains

Thin, flat-hanging curtains fitted against the glass of a window or door, or immediately over a shade, and usually kept drawn over the glass to soften the light and give privacy. For thin, often sheer curtains used under the main curtains to soften light, use "undercurtains." For curtains made of any transparent or very lightweight material, often plain white and often used as undercurtains, use "sheer curtains."

glass painting (image-making)

Painting done on the front or the reverse of glass, whether or not the paint is then fired onto the glass.

glass reinforced cement

Cement reinforced with alkali-resistant glass fibers.

glaze (coating by location)

Thin, usually glossy surface coating in various contexts. In paintings, glaze is a thin film of transparent to semitransparent color added to change tonality.For textiles and paper, glaze is a highly polished finish obtained by treating the fabric or paper with starch, glue, wax, or synthetic resins, then heat-pressing. In ceramics, glaze is a thin, vitreous, opaque coating fired on the surface of a ceramic body to add color, texture, and water resistance; prefer a narrower concept "ceramics glaze," or one of its narrower terms. For thin applications of paint in watercolor, use "wash (material)."

glazed header

In masonry, a header of darker color than the field of the wall.

glazed terracotta
No description is available for this term.

Gleditsia triacanthos (species)

Species of thorny tree native to regions in North and South America, Africa, and Asia. It produces a high quality wood. The long thorns were once used as nails. Currently, honey locusts are mainly grown as an ornamental tree; its slow growth minimizes potential for commercial use. It is not a significant honey plant; rather the common names derive from the sweet tasting pulp of the legume fruit, which was used for food by Native Americans and is fermented to make beer.


Adhesive comprising an impure protein obtained by hydrolysis of collagenous material such as skin, bone, and connective tissue by various methods.

glue-laminated timber

A type of structural lumber product composed of a wood core with several layers of wood veneer bonded to the front and back by durable adhesive known as laminating stock. Glue-laminated timber beams are used as an alternative to steel beams in construction due in part to the relative energy-efficiency of their manufacture which produces far less greenhouse gas emissions.


Metamorphic rock, commonly rich in quartz and feldspar with a banded and foliated texture comprising bands of light colored minerals that alternate with bands of dark colored minerals. It is composed of mica, quartz, and schist, with additional iron, magnesium and silicates. It is formed at temperatures above 550 degrees Centigrade. Gneiss is similar to granite in composition and may be classified as a type of granite, but it is produced by the alteration of igneous and sedimentary deposits, whereas granite is formed of igneous deposits.

gold (metal)

Pure metallic element having symbol Au and atomic number 79; a soft, inert, shiny reddish yellow metal that is very malleable and ductile. Gold has been highly valued and found in artifacts dating to before 5000 BCE. Native gold, found in quartz veins (vein gold) and alluvial deposits (placer gold), generally contains some silver and copper. Gold is purified by dissolution in mercury or cyanide solutions, by melting, or by electrodeposition. The purity of commercial gold is expressed in karats which is the number of parts of gold in 24 parts of the alloy. Today gold is primarily used for monetary systems and for jewelry.

gold leaf

Refers to sheets of gold that have been hammered or rolled very thin (typically around 0.1 micrometer, or 4 millionths of an inch, thick). In art, gold leaf has been applied to paintings, sculptures, manuscripts, and decorative arts since around 1500 BCE. In the 1920s, the process of creating gold leaf was successfully automated.

gold plating (process)

The process of coating an object with a thin adherent layer of gold.

Gothic Revival

Refers mainly to the style in English and American architecture and decorative arts from the mid-18th century to the mid-19th century. The style is characterized by the use of rosettes, pinnacles, tracery, foils, and polychrome effects inspired by Gothic architecture and reproduced with the aim of historical accuracy.


Casual scribbles or informal drawings on walls or other surfaces. Examples include the following: The casual scribbles or pictographs on walls, stones, or other surfaces in ancient and medieval times, the marks incised or cut into the underside of ancient Greek vases and other ceramics, and modern humorous, satiric, obscene, or gang-related writings or drawings executed anonymously in public places. Graffiti is distinct from "sgraffito," in that sgraffito is not casual, but is instead a formal decorative mark-making technique used on pottery, glass, or other surfaces. For more finished, elaborate works on modern walls and other surfaces, prefer "graffiti art."

grain (seed)

General term for the small, hard seeds of various species in different genera of the grass family Poaceae, used as cereal plants, such as wheat, rice, corn, rye, or oats.

granite (rock)

A coarse-grained igneous rock that has been subjected to metamorphic processes, formed by cooling of silica-rich magma below the surface of the earth at great depths and pressures. It is the most common intrusive acid igneous rock of the Earth's crust. Granite is commonly found on continents, but is virtually absent from the ocean basins. The term "granite" refers to its visible granular composition. It has a visibly crystalline texture, is usually red, whitish, or gray in color depending upon its composition, is very hard and durable, and takes a fine polish. Granite is primarily composed of feldspar, quartz, and mica along with various other minerals in varying percentages. Granite is frequently used for buildings and monuments.

graphite (mineral)

Naturally occurring crystalline form of carbon dimorphous with diamond. Graphite has a layered structure that consists of rings of six carbon atoms arranged in widely spaced horizontal sheets, and thus crystallizes in the hexagonal system, in contrast to the same element crystallizing in the octahedral or tetrahedral system as diamond, resulting in very different characteristics in each. Graphite is opaque, soft, greasy to the touch, and iron black to steel gray in color; it occurs as crystals, flakes, scales, veins, bedded masses, or disseminations in metamorphic rocks.

grass (plant material)

Material comprising the stalks or leaves of plants of the family Poaceae, and plants resembling these in general appearance.

grasses (plants)

Plants in the graminae family, and plants resembling those in appearance. Also, used generally to refer to herbage, especially herbage eaten by grazing animals.


Areas dominated by grasses rather than large shrubs or trees. One of the earth's six major biomes.


A coarse granular aggregate, larger than sand, formed either naturally or by crushing rock.

gray granite

Granite with a mineral composition that results in a gray color and typically fine texture.

gray iron (cast iron)

Pig or cast iron containing much graphite.

gray marble

Marble with a mineral composition that results in a predominantly gray color.

gray slate

Slate that is predominantly gray in color.

green glass (bottle glass)

Inexpensive glass, commonly of greenish or brownish color, which is caused by the presence of impurities, notably iron. It is often used to make bottles or windows. The term is derived from its resemblance to forest glass, which is also called "green glass."

green marble

Marble with a mineral composition resulting in a predominantly green color.

green slate

Slate that has a component of chlorite, causing a greenish color.

greenhouse glass

Low-grade double-strength drawn glass used in the construction of greenhouses; it is slightly wavy so it may cause slight distortion of images viewed through it.

greenstone (rock)

Any of various rocks that are green in color, including altered igneous rocks colored green by feldspar, hornblende, augite, nephrite, or other minerals, or low-grade metamorphic rock containing actinolite, epidote, or albite. Greenstone has been used for carving and construction.

groined vaults

Compound vaults in which barrel vaults intersect forming ridges called groins.


Mortar whose watery consistency allows it to be placed or pumped into small joints or cavities, as between pieces of ceramic clay, slate, or floor tile.


A substance that is found on some coasts or islands frequented by sea fowl, composed chiefly of their partially decomposed excrement, rich in phosphate and nitrogenous matter, used extensively as fertilizer. Also refers to excrement of bats.

gum (material)

Carbohydrate containing exudates obtained from some trees or shrubs belonging to the family Fabaceae of the pea order Fabales. Gum is insoluble in alcohol and either soluble or swellable in water. Some plant gums are used in the form of water solutions in the manufacture of cosmetics, pharmaceuticals, and foods; when the water evaporates, a film having a considerable adhesive character is formed. Some gums, such as gum arabic, dissolve in water to give clear solutions. Other gums, such as gum tragacanth, form mucilages by the absorption of large amounts of water. May be distinguished from "resin" in that gum hardens in drying, but is usually soluble in water.

gumwood (wood)

General term for wood of any of several species of trees of the genera Eucalyptus, Corymbia, and Angophora that exude copious sap or gum from any break in the bark. It is tough, has an interlocking grain, and is used for mallets, furniture, and bottle cases.


A construction material composed of cement, sand, or crushed slag and water forced through a pneumatic gun.


Naturally occurring soft white mineral that is commonly used as a retarding agent in portland cement, as a core in sheets of wallboard, as a white pigment, in grounds for paintings, and is the main component of alabaster.

gypsum board
No description is available for this term.

gypsum plaster

Any of the common types of wall plaster in general use, all of which contain various amounts of gypsum.

half-timber construction

The vernacular building technique in which the spaces between the heavy supporting timbers are filled with brick, wattle and daub, or other material. The term is also used to describe buildings with a false-timber frame attached to the outside wall to give the appearance of half-timber construction.

hammer-beam trusses

Trusses of the type utilized in hammer-beam roofs, with a combination of hammer beams, hammer posts, and braces taking the place of the beam at the base of the roof.

handmade brick

Any brick molded by hand before firing; a brick mold or stock may be used. Due to the fact that it is less uniform than machine-made brick, it is sometimes preferred for facing.

hard-burned brick

A brick that has been burned at high temperature, yielding high compressive strength and durability and low absorption.


Wood produced from broad-leaved deciduous trees, varying widely in color and grain pattern; usually but not always harder than softwood. Examples of hardwood trees are ash, beech, birch, cherry, mahogany, maple, oak, poplar, and walnut. Hardwood trees are found in temperate and tropical climate zones. Most of the wood used for cabinetry, furniture and flooring is obtained from hardwood trees; only a small amount of hardwood is used for paper pulp. The term hardwood is somewhat confusing since some deciduous trees, such as basswood, have timber that is softer than some coniferous trees, such as yellow pine.

hay (material)

General term for material comprising grass that has been mown, cut, and cured; often used as fodder.

heat-absorbing glass

Glass that absorbs heat because it is opaque to infrared radiation; it nevertheless retains a reasonable degree of transparency to most other radiation.


Lines of closely spaced hedges typically interspersed with trees, usually planted on a low earthen wall or base and trained to form a barrier or mark the boundary of an area, particularly in fields or between properties.

hematite (mineral)

A metallic black-gray or dark red mineral primarily composed of iron oxide found throughout the world, although the largest source is a sedimentary deposit in the Lake Superior district in North America. It occurs in many physical forms: specular ore (steel gray color, shiny crystals); micaceous hematite (gray, scaly flakes), red ocher (soft, fine-grain, red powder); kidney ore (massive, gray botryoidal form), and pencil ore (gray, fibrous crystals). Because hematite has a high iron content (70%), it is primarily used for smelting iron. It also has been used since ancient times as a red pigment in paints and glazes, for seals, beads, and small carvings since the early 3rd millineum. It is also used as jewelers' rouge for polishing glass and to produce the sparkle in aventurine ceramic glazes.

hemlock (wood)

Wood of the tree from the genus Tsuga. The bark contains tannin, used in the tanning industry, and the timber is mostly light in color with a pinkish tinge, and the soft, and coarse-grained, used in construction of boxes.

herbaceous plants

Perennial plants which have no woody stem, and which can be divided into three types: annuals, biennials, and herbaceous perennials.


Any chemical agent that is toxic to some or all plants, particularly those categorized as weeds. Historically a variety of substances have been used including salts, carbon disulfide, borax, pyridine, mercurials, and arsenic trioxide. After 1945 synthetic varieties emerged including: amitrole, picloram, 2,4-D, DDT, atrazine, glyphosate, diquat, and paraquat. Herbicides do not always decompose and have created environmental hazards.

hickory (wood)

Wood of the tree belonging to the genus Carya, valued because it is strong, elastic, and shock resistant. The reddish brown wood has a straight grain and a fine texture that polishes well; used for flooring, tool handles, farm implements, chairs, wheel spokes, golf clubs, baseball bats, and for flavoring smoked food. It is also split into thin canes for weaving. The heartwood is white.


Small hills, small elevations in the earth's surface, or small mounds or heaps of earth or stones.

hip roofs

Roofs which rise to a peak or ridge by inclined planes on all, usually four, sides, therefore requiring hip rafters.

hollow brick

A hollow clay masonry unit whose net cross-sectional area in every plane parallel to the bearing surface is not less than 60% of its gross cross-sectional area measured in the same plane. In British usage it refers to a brick with holes in it that total at least 25% of its volume, the holes being not less than 3/4 in. (1.91 cm) wide or 3/4 sq. in. (4.84 sq. cm) in area.

hollow masonry units

Masonry units whose net corss-sectioned area in any plane parallel to the bearing surface is less than 75% of its gross cross-sectional area measured in the same plane.

honey locust (wood)

Wood of the species Gleditsia triacanthos, native to regions in North and South America, Africa, and Asia. It produces a high quality wood that polishes well, but is lighter and weaker than most locust wood. It is used for specialty furniture, wheel spokes, and posts.

hyacinth (zircon)

A transparent red or brown variety of zircon, sometimes used as a gem.

igneous rock

Any of various crystalline or glassy rocks formed by the cooling and solidification of magma or other molten earth material. Igneous rocks comprise one of the three principal classes of rocks, the others being metamorphic and sedimentary.

Ilex (genus)

Genus containing around 400 species of red- or black-berried plants, including the popular Christmas hollies grown for ornamentation. Timber from the holly has a fine uniform texture. The trees provide shelter, protection from predators, and food for birds, other animals, and insects; the berries are mildly poisonous to humans. Ilex is the only living genus in the family Aquifoliaceae.

impregnated wood

Wood impregnated with thermosetting resin then subjected to heat and pressure to provide both resin curing and compression.

Indian red (pigment)

Synthetically produced brick red color iron oxide artists' pigment. Originally, the name "Indian red" was used for red earth pigments imported from the Persian Gulf and India; in the early 18th century, a synthetic Indian red composed of pure ferric oxide was made from steel mill wastes. It is a dense, opaque, permanent pigment.

Indiana limestone

A noncrystalline massive rock with aggregate filler and a matrix of 98% calcium carbonate in gray and buff colors; it is an oolitic limestone with small round grains resembling fish roe. Almost half of all the limestone used in the United States in block form is Indiana limestone.


Mass of any type of metal, cast into convenient shape for storage and transportation, to be rolled, forged, melted, or otherwise processed later. In some periods and cultures, such as in China, ancient Italy, and parts of Africa, they have been used as currency and as ceremonial objects.


Words, texts, lettering, or symbols marked on a work, including texts, legends, documentation notes, or commemoration. For standardized symbols or notations on objects that convey official information, use "marks (symbols)."

insulating glass

Window glass made of two sheets of glass separated by metal bonded to the edges of the glass, leaving an insulating layer of dehydrated air between the two panes.


A substance that is a nonconductor, so as to prevent the passage of heat, electricity, or sound.

interior shutters

Shutters, typically made of wood, mounted on the inside wall of a house, covering a window.

ipe wood
No description is available for this term.

iron (metal)

Pure metallic element having symbol Fe and atomic number 26; metallic iron is silvery in color, lustrous, soft, ductile, malleable, and slightly magnetic; it rusts when exposed to moist air. It is rarely found as a native metal (telluric iron) except in meteorites (meteoric iron). Iron is most often found throughout the world as iron oxides (hematite, magnetite, limonite, and siderite) mixed with other ores.

iron alloy

Alloy in which iron is the principle element.


General term for exceptionally tough or hard wood from any of numerous species of trees and shrubs, such as ebony, hornbeam, or acacia.

ironwork (visual works)

Visual works or parts of works made of iron, generally reserved for decorative forms fashioned in wrought or cast iron.

Italian marble
No description is available for this term.


Any red chert or chalcedony.

juniper (wood)

Wood of the genus Juniperus, evergreen shrubs or trees, of which numerous species are found variously in the northern hemisphere; used in joinery.

Juniperus (genus)

Genus containing 60 to 70 species of aromatic evergreen trees or shrubs.

Juniperus virginiana (species)

Species of juniper native to eastern North America, from southeastern Canada to the Gulf of Mexico.

junk bottles

Black- or green-glass bottles of quart and pint sizes, used primarily for beers, porter, cider, spring water, and other popular potables.

junk sculpture

Works composed primarily of industrial and modern consumer-culture waste, usually presented as assemblages of found objects.

jute (fiber)

Bast fiber derived from either of two East Indian plants (Corchorus olitorius and C. capsularis). The pale brown fibers are soft, lustrous, and coarse, ranging in length from 4 to 10 feet. The brittle fibers are used to produce a thread called hessian. Jute becomes so weak when wet that a thin twine can be broken by hand. It turns brown and degrades with time, sunlight, water, acids, alkalis, and bleach. Jute has been used since prehistoric times. It is used to make sackcloth, burlap cloth, gunnysacks, twine, paper, and carpet backing. It was also used to make brown paper in Europe in the mid-19th century.

kiln-dried lumber

Lumber that has been dried with the use of artificial heat in a kiln (oven).

king-post trusses

Triangular frames with a vertical central strut (the king post) extending from apex to tie beam.

koa (wood)

Hard, golden-brown wood of the species Acacia koa, native to Hawaii. The color and grain pattern of koa wood changes with growing conditions and tree age. It is a lightweight, but durable wood, that is brittle with variations in density. Koa is difficult to work or plane but carves well and polishes to a high gloss, used for carvings, boats, dugout canoes, early surfboards, veneers, musical instruments, and furniture. It was the royal wood of the native Hawaiians and was used for everything that came in contact with the royal family.

laburnum (wood)

Wood of the trees of the genus Laburnum, having a striking, dark greenish brown or reddish brown color, fine grain, and capable of taking a high polish. It is typically used for cabinetmaking and inlay.

lac (resin)

A resinous substance excreted by the lac insect, especially those who live on the twigs and soft new branches of several varieties of soapberry and acacia trees. Lac is used in the manufacture of varnishes (shellac), sealing wax (lac wax), and red colorants (lac dye) as early as ca. 1200 BCE in India. The word "lac" is the English version of Persian and Hindi words meaning "hundred thousand," indicating the large number of the tiny insects required to produce lac.

lacquer (material)

Paint, varnish, or another material applied by coating, made of the resinous exudation of certain trees or from insects, and that dries with a high gloss or matte finish. In most lacquers resin is dissolved in a volatile solvent or a drying oil and hardens by evaporation. Lacquer may be applied in many layers, so the thick surface may be set with inlays or carved.

lagoons (bodies of water)

Bodies of shallow water separated from the sea by a barrier, such as a sandbar or coral reef.


Flexible material made by bonding together two or more layers of materials with adhesive. For resin-impregnated laminate, such as paper or fabric, use "plastic laminate." For thin sheets of layered plastic, use "laminated plastic."

laminated veneer lumber

Lumber produced by overlaying and adhering multiple layers of thin wood. This composite wood product is stronger and more uniform than conventional milled lumber and less likely to warp or shrink.

lantern lights

Raised skylights or small lanterns with the sides mostly glazed, erected on a roof to admit light to the space below.