Triceps \Tri"ceps\, n. [NL., fr. L. triceps, having three beads; tres, tria, three + caput head: cf. F. triceps. See Three, and Chief.]

(Anat.) A muscle having three heads; specif., the great extensor of the forearm, arising by three heads and inserted into the olecranon at the elbow.

Source: Webster's Revised Unabridged Dictionary (1913)