brachio-

1.
a combining form meaning “arm,” “upper arm,” used in the formation of compound words:
brachiopod.
Also, especially before a vowel, brachi-.
Origin
combining form representing Latin brāchium and Greek brachī́ōn
British Dictionary definitions for brachio-

brachio-

combining form
1.
indicating a brachium: brachiopod
Word Origin and History for brachio-

before a vowel, brachi-, word-forming element meaning "arm," from Greek brakhion "arm," perhaps originally "upper arm," literally "shorter," and from brakhys "short" (see brief (adj.)), in contrast to the longer forearm.

brachio- in Medicine

brachio- pref.
Arm: brachiocephalic.