Illustrated Glossary of Architectural Terms
compiled by Chad Garrett Randl

Describing architecture from the recent past can be a challenge. Architectural and preservation dictionaries often do not contain vocabulary relevant to mid-twentieth century buildings. Although the terms for some materials and features remain in use, many others have faded as fashion and styles changed. This glossary is designed to assist in identifying recent past architecture for survey and documentation initiatives, advocacy efforts, nominations for state and national registers or for personal interest. Additional terms and images will be included in the future. If you would like to add definitions or photos, or if you have comments about the glossary, please email c_randl@hotmail.com.

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TERM	AKA	DEFINITION	IMAGE
accordion door		interior door assembled from narrow slats that fold into each other and flat against a door jamb or wall surface; uses are similar to a folding door
acoustical tile		cellulose fiber tiles often perforated with random drilled holes and beveled on edge; used in dropped ceilings, or secured to ceilings or walls with a mastic
A-frame		triangular-shaped structure in which the pitched roof also functions as a wall extending from the peak to the floor; particularly popular for vacation homes (1950s-1970s), though also used for churches and roadside commercial buildings
asbestos cement roofing shingles and siding shingles		thin, fire resistant roof and wall covering; most commonly in a white, gray, black, red or green color, may have a straight or wavy edge and a woodgrain or smooth finish; may be hexagonal or square to resemble wood shingles
awning		canvas, aluminum or corrugated glass-fiber panels set over a storefront, building entrance or window opening; provides shelter from inclement weather and reduces solar gain
baseboard heater	convector	hot water heat system usually with aluminum covers, installed along the baseboards of a room; considered an attractive alternative to radiators
breezeway	lanai	covered open area or passageway connecting a residence and its garage, two wings of a single building, or two separate buildings
block flooring		wood flooring composed of a series of square fabricated wood blocks, patterns included square, herringbone, continuous strip and rectangular, often used in schools, offices, factories, gymnasiums and homes
casement window		steel, aluminum or wood window that swings outward from hinges along the vertical joint (like a door); may be single paned or divided into multiple lights; common from the 1890s-1960s on Tudor Revival, Mission, Collegiate Gothic, Prairie, and other Modern buildings
concrete joist	Lith-I-Bar	machine rolled concrete framing member containing welded steel reinforcement bars, provided structural strength and fireproofing in one prefabricated package, beams were often left exposed on ceiling
corrugated glass		Inexpensive form of glass used frequently for skylights and sidewalls of industrial buildings - corrugations provided additional strength - combined with wire glass it was called CWG
Cor-ten	weathering steel, A242 steel	trade name for a corrosion resistant steel alloy that, when exposed to the environment, forms a dense adherent oxide coating that serves as a decorative finish while protecting from further corrosion; notable buildings constructed with Corten facades include Eero Saarinen's 1961 John Deere Building and the 1965 Richard Daley Center in Chicago
curtain wall	window wall, grid wall	outer skin of a building composed of modular glass, metal, plastic, ceramic or precast concrete panels often separated by mullions in a repeating grid; supported by a load bearing steel or concrete structural frame
dalle de verre	faceted glass, slab glass	thick, cast glass often chipped (or "faceted") along its edges and set in a matrix of concrete or epoxy; popular in the postwar period as a modern alternative to stained glass windows.
drawn glass		window glass made by drawing molten glass as flat sheets directly into an annealing oven; the process resulted in a glass that was more uniform in thickness, more flat with a minimum amount of distortion; it was the technological process chronologically located between blown cylinder glass and the current float glass process
exposed aggregate		concrete surface finish in which raised pebbles, stones or crystals are visible, colored aggregates often provided further decorative embellishment
exposed girder	mullion	steel or aluminum I-beam projecting from a curtain wall assembly, dividing window units and spandrel panels; because of fireproofing requirements, exposed girders were often non-loadbearing representations of the steel frame within the exterior wall
flanker	ventilator	the glass window units that are placed on either side of a single light picture window; if the windows are operable, especially casement or awning windows, they are often referred to as ventilators
float glass		contemporary sheet glass made by setting molten glass on bed of liquid tin; the result is an extremely polished and flat product
flush door		flat door with no raised or recessed panels
folded plate	shell structure	roof structure made of thin steel, concrete or plywood panels joined together in alternating peaks and valleys; various stiffeners or ties are placed at the ends of the plates, linking the tops of supporting columns; also used for canopies
folding door		a sectional partition often made of a Masonite or other pressed wood material core and a vinyl cover with nylon bearings that rides in a steel track, used as room door, closet door and room divider
glass block		hollow assemblies, usually eight or twelve inches square by four inches thick, that consist of two cast glass pieces fused together at high temperature; allowed for light transmission while providing insulation and a degree of privacy; were commonly used for bathroom windows, factory glazing, curved shopfronts, and interior partitions
Gold Chip linoleum		linoleum floor tiles inlaid with gold-like metal flecks
insulating glass	twindow, thermopane	two (and later three) sheets of glass separated often by a metal spacer bar with an air space between, twindow - pittsburgh plate glass, Thermopane - LOF
jalousie	louvered window	fixed window with louvres; each horizontal louvre pivots to open or close and is adustable by a crank; frequently used to enclose porches or for bathroom windows; louvres may be glass (often patterned), wood or aluminum; storm and screen windows can be placed on inside
Lannon Stone	Niagara Dolomite	porous, dolomite limestone used either in the form of blocks or as a veneer; one of the hardest and most versatile limestones; see:http://www.desmoinesartcenter.org/saarinen.html
lapped plywood siding		exterior grade plywood courses nailed to studs with shingle wedges under the vertical joints; panels could be purchased pre-cut or ripped on site
Masonite		hardboard made from wood fiber, wax and resins; used for exterior siding, interior wall surface and substrate,
mullion	exposed girder	vertical divider between window units or glass, metal or plastic modules in a curtain wall assembly.  Mullions were solid or I-shaped.
open web framing	v-purlin, web truss	steel joist or purlin with top and bottom plates connected by a continuous zigzag, or V-shaped, reinforcement rod; left exposed for decorative effect especially under open ceiling or canopy
ornamental ironwork		porch columns, rails, cornices, brackets, fences or gates, made of wrought or cast iron, simple hand wrought scroll work was commonly used on porches and entrances of contemporary homes
overhead sectional door		a spring-balanced garage or loading dock door with vertical joints between sections and with rollers set in a track that guides the opening door up and above. Each section was often divided into a row of square or rectangular recessed panels. In residential doors one of the upper rows would be glazed, service station and industrial doors often had several glazed rows
panel and batten siding		wall surface in which exterior grade plywood sheets are nailed to framing studs and the joints covered with wood battens
panel window system		grid of (usually horizontally oriented) windows; may be fixed or operable awning or hopper type windows, flat or bowed;
pass door	wicket door	small door in a larger overhead garage door that allows individuals to pass through closed parent garage door
patterned glass	textured glass	colored, clear, opaque, semi-opaque or transparent glass that has a variety of patterns rolled onto the glass surface, used for interior partitions, interior transoms and sidelights in office corridors, the most common types included hammered, ribbed, pebbled, and florentine, though patterns had a variety of trade names
Perma-stone	Bondstone, Formstone	trade name for a simulated masonry wall facing made of portland cement, aggregate, quartz, mineral colors and hardeners; manufactured off site or mixed on site and pressed with a mold onto a building exterior; appearance was usually as alternating bands of wide and narrow ledge stone; first introduced in 1929
picture window		large fixed sash window common on contemporary houses, may be flanked by casements, awning or double hung sash windows
plate glass		window glass made by pouring molten glass onto a table to cool and then grinding and polishing it to remove distortions and other flaws
Plyweave		trade name for embossed plywood sheet with beading pattern made by running fir plywood through heated pressure rolls - manufactured by Roddis Plywood Association in the early 1950s
pole construction		usually square structure raised above the ground and supported by round or square timbers six to twelve inches in diameter; the poles are carried from the ground to the roofline, forming the foundation, structural frame and an important design element
polyester glass fiber panel	fiberglass panel	corrugated or flat panel used in for awnings, car port roofs, canopy roofs and as elements of interior room partitions; may be translucent or opaque
porcelain enamel panel		a panel or tile with a steel base upon which a vitreous porcelain is fused, commonly used for the exteriors of commercial buildings and storefronts, porcelain enamel tiles were used in bathrooms and kitchens
prismatic glass	prism glass	glass designed to project daylight into the back areas of stores, offices and residences; came as patterned sheets that could be used to glaze transoms, upper sash, sidelights and interior partitions, or as pressed 4"x4" tiles that were assembled in a copper, zinc or lead framework and placed above shop display windows and entrances
projected window		vertically oriented window that includes both an outward projecting and inward projecting ventilator separated by fixed units, two or more projected windows were often set between mullions to form larger opening
prow		glazed gable end that angles outward like the prow of a ship.
pump island		Row of gas pumps usually set parallel to gas station, often connected to main structure by a canopy
radial folded plate roof		roof with tapered folded plates set over a circular or half circle structure; offers clear-span interior because strength of panels makes center supports unnecessary
radiant heating		steel pipes embedded in concrete floor slab through which hot water flows
redi-cut	pre-cut	houses sold as a kit; all the timber was delivered as a package cut to the proper size and marked for assembly, ready to be nailed into place
reverse board and batten siding		exterior grade plywood with inch wide shallow grooves eight inches on center
ribbon window		horizontal band of fixed or operable windows often with no intervening wall
roman brick		long thin brick (usually 2"x4"x12") commonly used in Prairie Style structures
shell structure		thin roof structure the strength of which is derived from a geometric apportioning of stresses; may be in wood or metal, though reinforced concrete is particularly well suited to shell forms; examples include hyperbolic paraboloids, short shells and folded plates  See: http://www.ketchum.org/ShellTandF/index.html for descriptions and drawings
shoji screen		partition consisting of bamboo panels with paper sandwiched between a horizontal grid; may be hinged & portable or fixed in a track; of Japanese origin
"Slide a Sash" window		two track window with two side by side sash, to open one sash slid along a track behind or in front of the adjacent sash
space frame		three-dimensional metal or plastic framework consisting of interlocking plates and chords; by distributing stresses in three dimensions they are structurally efficient; often used to span large areas with few supports
split-level		multi-story variation of the ranch house, developed in the 1930s, but most popular between the 1950s and 70s, a usual layout had a single story wing containing the front entrance, kitchen and dining room connected by half-flight stairs to a two-story section that had a garage and family room with bedrooms above
stressed skin panel		prefabricated wall or ceiling panel that consists of (4'x8') sheets of plywood glued to an internal (often 2"x4" lumber) frame and stringers.  Insulation and wiring are contained within the panel.  The frame and stringers function as built up I-beams that carried shear forces while the plywood skins carried compressive and tensile stresses and functioned as exterior and interior sheathing - they were seen as a way to prefabricate buildings and reduce construction time at the building site - developed in the 1930s by the USDA Forest Products Laboratory and later by the Douglas Fir Plywood Association
structural glass	Vitrolite, Carrara glass	opaque or semi-transparent glass panels; made by fusing at high temperature, rolling and polishing; most commonly found on storefronts and bathroom walls
sun shade	brise-soleil, sun break	features that are placed in front of above glazed areas to limit solar radiation and glare while allowing light and fresh air to filter through; louvered eave overhangs, perforated metal or concrete grilles hung along curtain walls, aluminum and wood slatted awnings and vertical "fins" placed on the side of windows were some sun shade types
sweep back gable roof	spent wing roof	pitched roof in which the ridgeline is longer than the eave lines
Texture 1-11 siding		textured siding/sheathing made with exterior grade fir plywood; two or four inch vertical grooves are formed by gluing plywood strips onto a plywood backing; marketed by the Douglas Fir Plywood Association
Thermopane	insulating glass	trade name for an early dual-pane insulating glass unit; two sheets of glass separated by a metal spacer bar with an air gap between; used for windows and sliding doors; manufactured by Libby Owens Ford
v-joint		manner in which plywood panels or wood planks were manufactured so that chamfered edges of two adjacent panels butted against each other to form an indented v-shape
vault light	vault covers	cast iron or concrete panel with glass lenses set in the sidewalk in front of a building; used to direct light into basements and lower level commercial spaces; popular between the 1870s and 1930s
ventilator	vent	any operable sash, especially casement, awning, pivot and hopper units, that are part of a larger window assembly that includes some fixed units
wire glass		glass in which a thin wire is embedded in the center of the sheet preventing the glass from shattering away from the frame upon impact or exposure to fire, wire could be woven into a hexagonal mesh similar to chicken wire or set in a diamond pattern, sheet may be clear flat or a range of opacities, or corrregated