coccobacillus vs eubacterium

coccobacillus and eubacterium both are nouns.

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

As nouns, eubacterium is a hypernym of coccobacillus; that is, eubacterium is a word with a broader meaning than coccobacillus:

coccobacillus: a bacterial cell intermediate in morphology between a coccus and a bacillus; a very short bacillus
eubacterium: a large group of bacteria having rigid cell walls; motile types have flagella

Other hypernyms of coccobacillus include eubacteria, true bacteria.

coccobacillus (noun)	eubacterium (noun)
a bacterial cell intermediate in morphology between a coccus and a bacillus; a very short bacillus	a large group of bacteria having rigid cell walls; motile types have flagella