roe vs spawn

roe and spawn both are nouns.

Word	Noun	Adjective	Verb	Adverb
roe	Yes	No	No	No
spawn	Yes	No	Yes	No

As nouns, spawn is a hypernym of roe; that is, spawn is a word with a broader meaning than roe:

roe (noun)	spawn (noun)
eggs of female fish	the mass of eggs deposited by fish or amphibians or molluscs
the eggs or egg-laden ovary of a fish
the egg mass or spawn of certain crustaceans such as the lobster
fish eggs or egg-filled ovary; having a grainy texture

roe (verb)	spawn (verb)
	lay spawn
	call forth