atom bomb vs fission bomb

atom bomb and fission bomb both are nouns.

Word	Noun	Adjective	Verb	Adverb
atom bomb	Yes	No	No	No
fission bomb	Yes	No	No	No

As nouns, atom bomb and fission bomb are synonyms defined as:

atom bomb and fission bomb: a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239)

Other synonyms of atom bomb include A-bomb, atomic bomb, plutonium bomb.

atom bomb (noun)	fission bomb (noun)
a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239)	a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239)