omentum vs peritoneum

omentum and peritoneum both are nouns.

Word	Noun	Adjective	Verb	Adverb
omentum	Yes	No	No	No
peritoneum	Yes	No	No	No

As nouns, peritoneum is a hypernym of omentum; that is, peritoneum is a word with a broader meaning than omentum:

omentum: a fold of peritoneum supporting the viscera
peritoneum: a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera

omentum (noun)	peritoneum (noun)
a fold of peritoneum supporting the viscera	a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera