fusion bomb vs atomic weapon

fusion bomb and atomic weapon both are nouns.

Word	Noun	Adjective	Verb	Adverb
fusion bomb	Yes	No	No	No
atomic weapon	Yes	No	No	No

As nouns, atomic weapon is a hypernym of fusion bomb; that is, atomic weapon is a word with a broader meaning than fusion bomb:

fusion bomb: a nuclear weapon that releases atomic energy by union of light (hydrogen) nuclei at high temperatures to form helium
atomic weapon: a weapon of mass destruction whose explosive power derives from a nuclear reaction

Other hypernyms of fusion bomb include bomb, nuclear weapon.

fusion bomb (noun)	atomic weapon (noun)
a nuclear weapon that releases atomic energy by union of light (hydrogen) nuclei at high temperatures to form helium	a weapon of mass destruction whose explosive power derives from a nuclear reaction