Triceps

['traɪseps] or ['traɪsɛps]

(noun.) any skeletal muscle having three origins (but especially the triceps brachii).

Edited by Edith--From WordNet

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

Checker: Sigmund

adj. three-headed.—Also Tricip′ital.

Checker: Sumner