nitrous bacteria vs eubacteria

nitrous bacteria and eubacteria both are nouns.

Word	Noun	Adjective	Verb	Adverb
nitrous bacteria	Yes	No	No	No
eubacteria	Yes	No	No	No

As nouns, eubacteria is a hypernym of nitrous bacteria; that is, eubacteria is a word with a broader meaning than nitrous bacteria:

nitrous bacteria: soil bacteria that oxidize ammonia to nitrites
eubacteria: a large group of bacteria having rigid cell walls; motile types have flagella

Other hypernyms of nitrous bacteria include eubacterium, true bacteria.

nitrous bacteria (noun)	eubacteria (noun)
soil bacteria that oxidize ammonia to nitrites	a large group of bacteria having rigid cell walls; motile types have flagella