eubacteria vs eubacterium

eubacteria and eubacterium both are nouns.

Word	Noun	Adjective	Verb	Adverb
eubacteria	Yes	No	No	No
eubacterium	Yes	No	No	No

As nouns, eubacteria and eubacterium are synonyms defined as:

eubacteria and eubacterium: a large group of bacteria having rigid cell walls; motile types have flagella

Other synonyms of eubacteria include true bacteria.

eubacteria (noun)	eubacterium (noun)
a large group of bacteria having rigid cell walls; motile types have flagella	a large group of bacteria having rigid cell walls; motile types have flagella