schoolmate vs friend

schoolmate and friend both are nouns.

Word	Noun	Adjective	Verb	Adverb
schoolmate	Yes	No	No	No
friend	Yes	No	No	No

As nouns, friend is a hypernym of schoolmate; that is, friend is a word with a broader meaning than schoolmate:

Other hypernyms of schoolmate include acquaintance.

schoolmate (noun)	friend (noun)
an acquaintance that you go to school with	a person you know well and regard with affection and trust
	a person with whom you are acquainted
	an associate who provides cooperation or assistance
	a person who backs a politician or a team etc.