"belonging to the arm, fore-leg, wing," etc., 1570s, from Latin brachialis, from brachium "arm," from Greek (see brachio-).
Entries linking to brachial
brachio-
before a vowel, brachi-, word-forming element meaning "arm, of the upper arm, pertaining to the upper arm and," from Latinized form of Greek brakhion "arm," perhaps originally "upper arm," literally "shorter," from brakhys "short" (from PIE root *mregh-u- "short"), in contrast to the longer forearm.