thermonuclear warhead vs atomic weapon

thermonuclear warhead and atomic weapon both are nouns.

Word	Noun	Adjective	Verb	Adverb
thermonuclear warhead	Yes	No	No	No
atomic weapon	Yes	No	No	No

thermonuclear warhead (noun)	atomic weapon (noun)
the warhead of a missile designed to deliver an atom bomb	a weapon of mass destruction whose explosive power derives from a nuclear reaction