omasum vs tum

omasum and tum both are nouns.

Word	Noun	Adjective	Verb	Adverb
omasum	Yes	No	No	No
tum	Yes	No	No	No

As nouns, tum is a hypernym of omasum; that is, tum is a word with a broader meaning than omasum:

omasum: the third compartment of the stomach of a ruminant
tum: an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion

Other hypernyms of omasum include breadbasket, stomach, tummy.

omasum (noun)	tum (noun)
the third compartment of the stomach of a ruminant	an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion