mediatrix vs go-between

mediatrix and go-between both are nouns.

Word	Noun	Adjective	Verb	Adverb
mediatrix	Yes	No	No	No
go-between	Yes	No	No	No

As nouns, go-between is a hypernym of mediatrix; that is, go-between is a word with a broader meaning than mediatrix:

Other hypernyms of mediatrix include intercessor, intermediary, intermediator, mediator.

mediatrix (noun)	go-between (noun)
a woman who is a mediator	a negotiator who acts as a link between parties