axilla vs axillary cavity

axilla and axillary cavity both are nouns.

Word	Noun	Adjective	Verb	Adverb
axilla	Yes	No	No	No
axillary cavity	Yes	No	No	No

As nouns, axilla and axillary cavity are synonyms defined as:

axilla and axillary cavity: the hollow under the arm where it is joined to the shoulder

Other synonyms of axilla include armpit, axillary fossa.

axilla (noun)	axillary cavity (noun)
the hollow under the arm where it is joined to the shoulder	the hollow under the arm where it is joined to the shoulder