tummy vs belly

tummy and belly both are nouns.

Word	Noun	Adjective	Verb	Adverb
tummy	Yes	No	No	No
belly	Yes	No	Yes	No

As nouns, belly is a hypernym of tummy; that is, belly is a word with a broader meaning than tummy:

Other hypernyms of tummy include paunch.

tummy (noun)	belly (noun)
an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion	the underpart of the body of certain vertebrates such as snakes or fish
slang for a paunch	the region of the body of a vertebrate between the thorax and the pelvis
	a protruding abdomen
	the hollow inside of something
	a part that bulges deeply

tummy (verb)	belly (verb)
	swell out or bulge out