order Passeriformes vs passeriform bird

order Passeriformes and passeriform bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Passeriformes	Yes	No	No	No
passeriform bird	Yes	No	No	No

order Passeriformes (noun)	passeriform bird (noun)
largest order of birds comprising about half the known species: rooks, finches, sparrows, tits, warblers, robins, wrens, swallows, etc.; the four suborders are Eurylaimi, Tyranni, Menurae and Oscines or Passeres	perching birds mostly small and living near the ground with feet having 4 toes arranged to allow for gripping the perch; most are songbirds; hatchlings are helpless