mesentery vs peritoneum

mesentery and peritoneum both are nouns.

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

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

mesentery: a double layer of peritoneum that attaches to the back wall of the abdominal cavity and supports the small intestines
peritoneum: a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera

mesentery (noun)	peritoneum (noun)
a double layer of peritoneum that attaches to the back wall of the abdominal cavity and supports the small intestines	a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera