axillary fossa vs axillary cavity

axillary fossa and axillary cavity both are nouns.

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

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

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

Other synonyms of axillary fossa include armpit, axilla.

axillary fossa (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