brachium

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.]

1. The arm, especially between the shoulder and the elbow.
2. An armlike structure.

Pl. brachia [L.]
1. the arm; specifically from the shoulder to elbow. Called also thoracic limb.
2. any armlike process or structure.

• b. colliculi caudalis — fibers from the caudal colliculus which enter the medial geniculate body and form part of the auditory pathway.
• b. colliculi caudalis et rostralis — the bridging fibers between the colliculi and the geniculate bodies.
• b. conjunctivum — the rostral cerebellar peduncle. A fibrous band extending from each hemisphere of the cerebellum upward over the pons, the two joining to form the sides and part of the roof of the fourth ventricle.
• b. pontis — the brachium of the pons, the middle cerebellar peduncle.

The noun has one meaning:

Meaning #1: (biology) a branching or armlike part of an animal