male parent vs pater

male parent and pater both are nouns.

Word	Noun	Adjective	Verb	Adverb
male parent	Yes	No	No	No
pater	Yes	No	No	No

As nouns, pater is a hyponym of male parent; that is, pater is a word with a more specific, narrower meaning than male parent:

male parent: a male parent (also used as a term of address to your father)
pater: an informal use of the Latin word for father; sometimes used by British schoolboys or used facetiously

Other hyponyms of male parent include dad, dada, daddy, pa, papa, pappa, pop, father-in-law, old man.

male parent (noun)	pater (noun)
a male parent (also used as a term of address to your father)	an informal use of the Latin word for father; sometimes used by British schoolboys or used facetiously