concave shape vs recess

concave shape and recess both are nouns.

Word	Noun	Adjective	Verb	Adverb
concave shape	Yes	No	No	No
recess	Yes	No	Yes	No

As nouns, recess is a hyponym of concave shape; that is, recess is a word with a more specific, narrower meaning than concave shape:

concave shape (noun)	recess (noun)
a shape that curves or bends inward	a pause from doing something (as work)
	an enclosure that is set back or indented
	an arm off of a larger body of water (often between rocky headlands)
	a small concavity
	a state of abeyance or suspended business