Acanthus - A plant whose leaf in stylized form is used to decorate the capital of the Corinthian order, and also to enrich moldings.

Adaptive Reuse - The use of a historic building for a purpose other than that for which it was constructed.  Adaptive reuse sometimes involves physical changes to the historic building, especially on the interior.

Adze (or Adz) - A cutting tool with an arching blade at right angles to the handle, used in the shaping of logs.

Arcade - A series of arches.

Arch - A curved construction which spans an opening.

Architrave - Member of an entablature that rests on the capitals of columns or piers and supports the frieze. Also, the trim of a door or window opening.
Arpent - a French term of measurement equaling approximately 192 feet.                .
Arts and Crafts - English movement in art and architecture during the second half of the nineteenth century which emphasized the importance of craftsmanship and high standards of design for everyday objects.

Awning - A roof-like cover (made of canvas or metal) extended over the space immediately adjacent to a building and used as a shelter. The words "awning" and "canopy" are used interchangeably.

Axial - Having an axis, i.e., an imaginary line dividing a plan or a facade into symmetrical parts.