barrel vault
the simplest form of vault consisting of an unbroken series of arches; it forms a tunnel like shape
groin vault
formed at the point at which 2 barrel vaults intersect at right angles
buttress
a support usually of stone or brick
pier
(architecture) a vertical supporting structure (as a portion of wall between two doors or windows)
coffers
is a sunken panel in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault
catacomb
an underground tunnel with recesses where bodies were buried (as in ancient Rome)
atrium
the central area in a building
nave
The long central part of a church, extending from the entrance to the altar, with aisles along the sides.
apse
a domed or vaulted recess or projection on a building especially the east end of a church
transept
The part of a church with an axis that crosses the nave at a right angle.
narthex
a vestibule leading to the nave of a church
Clerestory
part of an interior wall rising above the adjacent roof with windows admitting light
Ambulatory
the passage (walkway) around the apse in a basilican church or around the central space in a central-plan church
choir
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Pendentive
curved triangular supports for a dome