class Aves vs order Ciconiiformes

class Aves and order Ciconiiformes both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Aves	Yes	No	No	No
order Ciconiiformes	Yes	No	No	No

class Aves (noun)	order Ciconiiformes (noun)
(ornithology) the class of birds	order of chiefly tropical marsh-dwelling fish-eating wading birds with long legs and bills and (except for flamingos) unwebbed feet: herons, storks, spoonbills, flamingos, ibises