Architrave. Door frame surround, normally ornamental.  Also known as trim. Originally a simple, flat, structural lintel spanning an opening in a wall, it is the lowest part of the classical entablature. Subsequently a term used to describe any molded door or window frame.

Arris. The external edge of two surfaces,especially  wood and panel-doors.

Atrium - In the Roman period this was the inner courtyard of a house, left open to the sky, and generally built by the affluent urbam classes. In the 20th century the word has been adopted to describe dramatic enclosed glass-roofed indoor spaces associated with high-rise hotels and office buildings that are treated as substitutes for the public realm.

Archivolt - Onee of a series of concentric moldings on a Romanesque or a Gothic arch.

Baluster - Any of the small posts that make up a railing as in a staircase; may be plain, turned, or pierced.

Balustrade - The combination of railing held up by balusters.

Bead Molding - A small, cylindrical molding enriched with ornaments resembling a string of beads.

Boss - A carved stone positioned at the apex of a ribbed vault.

Canopy - A projection or hood over a door, window, niche, etc.

Capital - The elaboration at the top of a column, pillar, pier or pilaster.

Casement Window - A window that opens by swinging inward or outward much like a door. Casement windows are usually vertical in shape but are often grouped in bands.

Casing - The trim bordering the inside or outside of a window or door, commonly referred to as "inside" or "outside" casing.

Clerestory window - A window (usually narrow) placed in the upper walls of a room, usually at an angle, to provide extra light.

Column - A slender, upright structure, usually a supporting member in a building. Freestanding or self-supporting structural element carrying forces mainly in compression; either stone, steel, or brick, or more recently, concrete.

Corinthian - The type of Greek column characterized by simulated acanthus leaves.

Cupola - A small, dome-like structure, on top of a building to provide ventilation and decoration.

chair rail - a piece of molding placed about thirty inches above the floor to protect the wall from being marred by chair backs

cornice - a shallow, box-like structure, usually made of wood, fastened across the top of a window to conceal the drapery hardware.

Dado - The zone between a chair rail or lower part of a sill and the baseboard.

Doric - The simplest of the three classical orders of Greek architecture.

Dormer - The setting for a vertical window in the roof. Called a gable dormer if it has its own gable or shed dormer if a flat roof. Most often found in upstairs bedrooms.

finial - the decorative ornament at the top of an object or on ends of curtain rods

Hearth - The fireplace floor.

Ionic - The type of Greek column characterized by scroll-like decorations.

lambrequin - a cornice that completely frames the window; sometimes used interchangeably with valance or cantonniere

molding - decorative strips of wood used to conceal joints and give a more decorative finished look

mullion - the vertical wood or masonry sections between a series of window frames.

Newel - The terminating baluster at the lower end os a handrail.

niche - a recess in a wall often used to display sculpture.

Oriel - A box-like window projecting from the wall of a house.

Palladian - A motif having three openings, the center one being arched and larger than the other two.  

Pediment - A low triangular gable above a cornice, topped by raking cornices and ornamented.. Used over doors, windows or porches. A classical style.

Pilaster - A rectangular vertical member projecting only slightly from a wall, with a base and capital as will a column.

Portico - A large porch usually with a pediment roof supported by classical columns or pillars.

Raking Cornice - The sloping moldings of a pediment.

Sash - An individual window unit (comprised of rails, stiles, lites, muntins) that fits inside the window frame.

Sidelights - Windows on either side of a door.

Solar Orientation - The relationship of room to the sun's light.

Spandrel - The part of a porch facade that reflects the balustrade.

sconce - a wall-mounted light fixture.

Transom - A small window just above a door.

wainscot - paneling; often used to refer to the lower part of an interior wall when finished differently from the remainder of the wall.