amphimixis vs isogamy

amphimixis and isogamy both are nouns.

Word	Noun	Adjective	Verb	Adverb
amphimixis	Yes	No	No	No
isogamy	Yes	No	No	No

As nouns, isogamy is a hyponym of amphimixis; that is, isogamy is a word with a more specific, narrower meaning than amphimixis:

amphimixis: reproduction involving the union or fusion of a male and a female gamete
isogamy: (biology) reproduction by the union or fusion of gametes of the same size and structure

Other hyponyms of amphimixis include anisogamy.

amphimixis (noun)	isogamy (noun)
union of sperm and egg in sexual reproduction	(biology) reproduction by the union or fusion of gametes of the same size and structure
reproduction involving the union or fusion of a male and a female gamete