first stomach vs ruminant

first stomach and ruminant both are nouns.

Word	Noun	Adjective	Verb	Adverb
first stomach	Yes	No	No	No
ruminant	Yes	Yes	No	No

first stomach (noun)	ruminant (noun)
the first compartment of the stomach of a ruminant; here food is collected and returned to the mouth as cud for chewing	any of various cud-chewing hoofed mammals having a stomach divided into four (occasionally three) compartments

first stomach (adjective)	ruminant (adjective)
	related to or characteristic of animals of the suborder Ruminantia or any other animal that chews a cud