noun
triceps
Anatomical term for the triceps brachii muscle on the back of the upper arm.
腕立て伏せは三頭筋を鍛えるのに効果的だ。
Push-ups are effective for training the triceps.
From 三 (three) + 頭 (head) + 筋 (muscle), a direct translation of the Latin 'triceps' meaning 'three-headed'.