division Eubacteria vs eubacterium

division Eubacteria and eubacterium both are nouns.

Word	Noun	Adjective	Verb	Adverb
division Eubacteria	Yes	No	No	No
eubacterium	Yes	No	No	No

division Eubacteria (noun)	eubacterium (noun)
one-celled monerans having simple cells with rigid walls and (in motile types) flagella	a large group of bacteria having rigid cell walls; motile types have flagella