Emily Dickinson Lexicon

ARCH'I-TRAVE, n. [Gr. αρχος, chief, and It. trave, from 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 hypertherion. – Johnson. Encyc. Cyc.