niche vs incurvature

niche and incurvature both are nouns.

Word	Noun	Adjective	Verb	Adverb
niche	Yes	No	No	No
incurvature	Yes	No	No	No

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

Other hypernyms of niche include concave shape, concavity, incurvation.

niche (noun)	incurvature (noun)
an enclosure that is set back or indented	a shape that curves or bends inward
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)