metatherian vs mammal

metatherian and mammal both are nouns.

Word	Noun	Adjective	Verb	Adverb
metatherian	Yes	No	No	No
mammal	Yes	No	No	No

As nouns, mammal is a hypernym of metatherian; that is, mammal is a word with a broader meaning than metatherian:

metatherian: primitive pouched mammals found mainly in Australia and the Americas
mammal: any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk

Other hypernyms of metatherian include mammalian.

metatherian (noun)	mammal (noun)
primitive pouched mammals found mainly in Australia and the Americas	any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk