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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A principal ore of lead; lead sulfide (PbS). Often contains silver.

galvanized steel

Steel coated with a thin layer of zinc to prevent corrosion. The application may be effected by electroplating or spraying the steel with molten zinc, or by coating the heated steel with zinc powder.

gardens (open spaces)

Area of ground or open space where flowers, shrubs, trees, vegetables, or fruits are grown and cultivated.

garnet (mineral)

A general name for a type of mineral varying in color and hardness, including trisilicates of aluminum, magnesium, calcium, iron, manganese, vanadium, chromium, and sometimes sodium and titanium. Used for coating abrasive paper and cloth, for bearing pivots in watches, for electronics, and the finer specimens as gemstone.

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.