concavity vs recession

concavity and recession both are nouns.

Word	Noun	Adjective	Verb	Adverb
concavity	Yes	No	No	No
recession	Yes	No	No	No

As nouns, recession is a hyponym of concavity; that is, recession is a word with a more specific, narrower meaning than concavity:

concavity (noun)	recession (noun)
the property possessed by a concave shape	the act of becoming more distant
a shape that curves or bends inward	the act of ceding back
	the withdrawal of the clergy and choir from the chancel to the vestry at the end of a church service
	a small concavity
	the state of the economy declines; a widespread decline in the GDP and employment and trade lasting from six months to a year