1706, "bone of the upper arm," originally (14c.) "shoulder," from Latin humerus, a common spelling of umerus "shoulder," from PIE *om(e)so- "shoulder" (source also of Sanskrit amsah, Greek ōmos, Old Norse ass, Gothic ams "shoulder"). Blount's "Glossographia" (1656) has humerous (adj.) "That hath great shoulders."
