Architecture terms explained: what a cupola, portico, pediment, cornice, colonnade, rotunda, facade, keystone and 20 other words mean, with the buildings that show them

Architecture · 4 September 2026

Most of the words used to describe buildings are Greek, Latin, Italian and French and were fixed by the Renaissance, when architects wrote the treatises that named the parts of a classical temple, and they are still the words on the guidebook, the listing and the plaque; here are the thirty most looked-up, each with what the thing is, what it does, where the word comes from and a building to see it on, from the United States Capitol, which has most of them at once, to the Pantheon. The styles the words belong to are in Ancient Greek architecture, Gothic architecture and Neoclassical architecture; the buildings themselves in the Buildings by style collection.

The roof and the top

• Cupola. A small dome or domed structure on top of a roof or a larger dome, from the Italian for "little cup"; on a house or barn it is a small square or octagonal turret with windows or louvres for light and ventilation, on a public building the lantern on top of the dome that lets light into it. See the Capitol's lantern, or any New England barn. A cupola on a shed is for airing the hay.
• Dome. A roof in the form of a half-sphere or a shell, an arch rotated around its centre, which pushes outward all round and needs a heavy base, a ring or chains; the Pantheon's is concrete, Florence's brick, St Paul's a triple shell. The drum is the cylindrical wall the dome stands on, usually with windows; the oculus is a round opening at the top, as at the Pantheon; the lantern the small structure that covers the opening and lets in light.
• Spire. A tall pointed structure on top of a tower, of stone, timber or lead, a Gothic invention to make the tower point at heaven; Salisbury's is 123 m. A steeple is the tower and spire together, the word used for churches in Britain and America.
• Turret. A small tower, usually round, attached to a corner of a building and projecting from it, on castles for defence and on Victorian houses for show; a turret that starts partway up the wall on a corbel is a bartizan.
• Belvedere. "Beautiful view" in Italian: a room, turret or open gallery on a roof or hill built to enjoy the view; the Belvedere courtyard of the Vatican is the origin.
• Dormer. A window that projects from a sloping roof in its own small roof, to light the attic; from the French dormir, because the attic was where people slept. A mansard roof has two slopes on each side, the lower steeper, to make an attic storey, named for François Mansart and the sign of Second Empire buildings.
• Gable. The triangle of wall under the two slopes of a pitched roof at the end of a building; a pediment is the classical version.

The front

• Facade. The face of a building, from the Italian facciata, usually the front one that faces the street or square and is designed to be seen; a building has a facade on each side, but "the facade" is the front. A false front is a facade taller than the building behind it, as on Western main streets.
• Portico. A porch with a roof carried on columns, usually with a pediment, in front of the entrance of a temple, church, house or public building; the Pantheon's has sixteen columns, Monticello's four, the White House's North Portico four. A portico on a house is the classical porch; a porch is the general word.
• Pediment. The low triangle above a portico or a door, formed by the two slopes of the roof and the horizontal cornice below them, filled with sculpture on temples, the Parthenon's with the gods; over a window or door it is a small one, and a broken pediment, with the top or bottom line interrupted, is a Baroque and Georgian flourish. A tympanum is the space inside it, or inside the arch over a church door.
• Colonnade. A row of columns carrying a horizontal entablature rather than arches, along a facade, around a courtyard or standing free, as around St Peter's Square; a peristyle is a colonnade around a temple or a court. An arcade is a row of arches on columns or piers, as in a cloister or a covered shopping street.
• Loggia. A gallery or room open on one side through a colonnade or arcade, Italian, on the upper floor of a palace or the ground floor of a square; the Loggia dei Lanzi in Florence.
• Cornice. The horizontal moulding that projects along the top of a wall or building, under the roof, to throw rain off and to finish the composition; on a classical building it is the top part of the entablature, on a house the strip under the eaves, and inside a room the moulding where wall meets ceiling. On a mountain it is an overhanging lip of snow, the same word.
• Quoin. The dressed stones at the corner of a building, laid alternately long and short, larger or of a different stone from the wall, to strengthen the corner and to show it; from the French coin, corner.
• Pilaster. A flat column attached to a wall, projecting a little, with a base and a capital, doing no structural work and marking the bays; Michelangelo's giant pilasters on the Capitol in Rome and St Peter's run through two storeys.
• Rustication. Masonry with the joints cut deep and the faces left rough or bevelled, to make the ground floor of a palace look strong; Florence's Palazzo Pitti.

The classical parts

• Column. A round vertical support, with a base (except Doric), a shaft, often fluted, and a capital at the top, where it meets the load; a pier is a square or compound support, a post a wooden one.
• The orders. The Greek and Roman systems of column and entablature: Doric, plain capital, no base, sturdy, the Parthenon; Ionic, capital with two scrolls (volutes), slender, the Erechtheion; Corinthian, capital of acanthus leaves, tall, the Pantheon and most of Washington; Tuscan, the plain Roman Doric; Composite, Ionic scrolls on Corinthian leaves. The order fixes the proportions of everything above and below.
• Entablature. The horizontal beam carried by the columns, in three bands: the architrave at the bottom, the plain beam; the frieze in the middle, often carved, with the Parthenon's procession or the Doric alternation of triglyphs and metopes; and the cornice on top.
• Keystone. The wedge-shaped stone at the top of an arch, set last, which locks the other stones (the voussoirs) in place; until it is in, the arch stands only on its timber centering. Often carved with a head or a bracket, and on a building's front door a mark of the classical style. The word is used for anything that holds a system together, and Pennsylvania is the Keystone State because it held the thirteen colonies together.
• Arch. A curved structure spanning an opening and carrying the load above it down to the sides by compression; round in Rome and Romanesque, pointed in Gothic, horseshoe in Islamic Spain, ogee in Venice. An archivolt is the moulding around it, an impost the block it springs from, a spandrel the triangle of wall between two arches.
• Vault. An arched ceiling of stone or brick: a barrel vault is a continuous arch like a tunnel, a groin vault two barrel vaults crossing, a rib vault a groin vault with stone ribs along the edges, the Gothic kind, and a fan vault the English 15th-century kind with ribs spreading like a fan, at King's College Chapel.
• Buttress. A mass of masonry built against a wall to resist the thrust of a vault; a flying buttress carries the thrust over the aisle on an arch to a pier outside, explained in what is a flying buttress.

Inside

• Rotunda. A round room or building, usually under a dome, from the Pantheon, "la Rotonda"; the Capitol's rotunda is 29 m across under the dome, Jefferson's Rotunda at the University of Virginia is a half-size Pantheon, and Palladio's Villa Rotonda is a house around one. A rotunda in a station or a bank is the round hall.
• Atrium. The central open court of a Roman house, with the roof sloping inward to a pool; in a modern office building, a glazed central hall rising through the floors; in a church, the forecourt.
• Nave. The main body of a church, where the congregation stands, from the Latin for ship; the aisles run beside it behind the piers, the transept crosses it to make the plan a cross, the crossing is where they meet, often under a tower or dome, the choir or chancel is the part beyond it for the clergy, and the apse is the semicircular end, usually east, where the altar stands. The ambulatory is the aisle around the apse, the narthex the porch or vestibule at the west end.
• Clerestory. The upper part of the nave wall, above the aisle roofs, with the windows that light the nave; "clear storey". The triforium is the band of arches below it, in front of the aisle roof, and the gallery or tribune an upper floor over the aisle.
• Crypt. A vaulted room under a church, for tombs and relics; Chartres's is the largest in France.
• Coffer. A sunken panel in a ceiling or dome, to lighten it and decorate it; the Pantheon's five rings.
• Mezzanine. A low storey between two main ones, usually between the ground floor and the first; from the Italian for middle.
• Pilotis. Columns that lift a building off the ground, leaving the ground floor open, Le Corbusier's word and the modernist house's trademark.

Versions and theories: the common confusions

• Cupola and dome. A cupola is small, on top; a dome is the roof. Americans call the Capitol's dome a dome and the thing on top of it a cupola or lantern.
• Portico and porch. A portico has columns and usually a pediment; a porch is any covered entrance.
• Pediment and gable. The same triangle; pediment when it is classical, with a cornice along its base, gable when it is the plain end of a roof.
• Colonnade and arcade. Columns carrying a straight beam versus columns carrying arches.
• Facade and front. The facade is any designed face; the front is the main one.
• Rotunda and dome. The rotunda is the room; the dome is its roof.
• Keystone and capstone. The keystone is the top of an arch; a capstone is the top stone of a wall or a pyramid.

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