stay together vs remain

stay together and remain both are verbs.

Word	Noun	Adjective	Verb	Adverb
stay together	No	No	Yes	No
remain	No	No	Yes	No

As verbs, remain is a hypernym of stay together; that is, remain is a word with a broader meaning than stay together:

Other hypernyms of stay together include rest, stay.

stay together (verb)	remain (verb)
be loyal to one another, especially in times of trouble	stay the same; remain in a certain state
	be in a certain place and not leave
	continue in a place, position, or situation
	be left; of persons, questions, problems, results, evidence, etc.