convolution vs round shape

convolution and round shape both are nouns.

Word	Noun	Adjective	Verb	Adverb
convolution	Yes	No	No	No
round shape	Yes	No	No	No

As nouns, round shape is a hypernym of convolution; that is, round shape is a word with a broader meaning than convolution:

convolution (noun)	round shape (noun)
the action of coiling or twisting or winding together	a shape that is curved and without sharp angles
a convex fold or elevation in the surface of the brain
the shape of something rotating rapidly