pharyngeal recess vs niche

pharyngeal recess and niche both are nouns.

Word	Noun	Adjective	Verb	Adverb
pharyngeal recess	Yes	No	No	No
niche	Yes	No	No	No

As nouns, niche is a hypernym of pharyngeal recess; that is, niche is a word with a broader meaning than pharyngeal recess:

Other hypernyms of pharyngeal recess include corner, recess, recession.

pharyngeal recess (noun)	niche (noun)
a small recess in the wall of the pharynx	an enclosure that is set back or indented
	a small concavity
	a position particularly well suited to the person who or organization which occupies it
	(ecology) the status of an organism within its environment and community (affecting its survival as a species)