concavity vs depression

concavity and depression both are nouns.

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

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

concavity (noun)	depression (noun)
the property possessed by a concave shape	pushing down
a shape that curves or bends inward	sad feelings of gloom and inadequacy
	a sunken or depressed geological formation
	angular distance below the horizon (especially of a celestial object)
	a concavity in a surface produced by pressing
	a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity
	an air mass of lower pressure; often brings precipitation
	a long-term economic state characterized by unemployment and low prices and low levels of trade and investment
	a state of depression and anhedonia so severe as to require clinical intervention