architrave

'ARCHITRAVE, n. [Gr. chief, and L. trabs, a beam.]

In architecture, the lower division of an entablature, or that part which rests immediately on the column. It probably represents the beam which, in ancient buildings, extended from column to column, to support the roof.

In chimneys, the architrave is called the mantle piece; and over doors and windows, the hyperthyrion.