Webster's Revised Unabridged Dictionary · 1913

Triclinium

Triclinium , noun

[Latin, from Greek {not transcribed}, {not transcribed}; {not transcribed} (see Tri-) + a couch.]

(a)
(Rom. Antiquities) A couch for reclining at meals, extending round three sides of a table, and usually in three parts.
(b)
(Rom. Antiquities) A dining room furnished with such a triple couch.