ovum vs gamete

ovum and gamete both are nouns.

Word	Noun	Adjective	Verb	Adverb
ovum	Yes	No	No	No
gamete	Yes	No	No	No

As nouns, gamete is a hypernym of ovum; that is, gamete is a word with a broader meaning than ovum:

ovum: the female reproductive cell; the female gamete
gamete: a mature sexual reproductive cell having a single set of unpaired chromosomes

ovum (noun)	gamete (noun)
the female reproductive cell; the female gamete	a mature sexual reproductive cell having a single set of unpaired chromosomes