triceps brachii vs triceps

triceps brachii and triceps both are nouns.

Word	Noun	Adjective	Verb	Adverb
triceps brachii	Yes	No	No	No
triceps	Yes	No	No	No

As nouns, triceps is a hypernym of triceps brachii; that is, triceps is a word with a broader meaning than triceps brachii:

triceps brachii: the skeletal muscle having three origins that extends the forearm when it contracts
triceps: any skeletal muscle having three origins (but especially the triceps brachii)

triceps brachii (noun)	triceps (noun)
the skeletal muscle having three origins that extends the forearm when it contracts	any skeletal muscle having three origins (but especially the triceps brachii)