concave shape vs incurvature

concave shape and incurvature both are nouns.

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

As nouns, concave shape and incurvature are synonyms defined as:

Other synonyms of concave shape include concavity, incurvation.

concave shape (noun)	incurvature (noun)
a shape that curves or bends inward	a shape that curves or bends inward