Proboscidea vs subclass Eutheria

Proboscidea and subclass Eutheria both are nouns.

Word	Noun	Adjective	Verb	Adverb
Proboscidea	Yes	No	No	No
subclass Eutheria	Yes	No	No	No

Proboscidea (noun)	subclass Eutheria (noun)
an order of animals including elephants and mammoths	all mammals except monotremes and marsupials
in some classifications included in the genus Martynia and hence the two taxonomic names for some of the unicorn plants