bra·chi·um 
(brākē-əm, brăkē-)
(brākē-əm, brăkē-)n. pl. bra·chi·a (brākē-ə, brăkē-ə)
1. The part of the upper arm or forelimb extending from the shoulder to the elbow.
2. An arm or a homologous anatomical structure, such as a flipper or wing.
3. The part of a limb or process corresponding to an arm.
[Latin brācchium, arm, from Greek brakhīōn, upper arm; see mregh-u- in the Appendix of Indo-European roots.]