chorus vs musical group

chorus and musical group both are nouns.

Word	Noun	Adjective	Verb	Adverb
chorus	Yes	No	Yes	No
musical group	Yes	No	No	No

As nouns, musical group is a hypernym of chorus; that is, musical group is a word with a broader meaning than chorus:

Other hypernyms of chorus include musical organisation, musical organization.

chorus (noun)	musical group (noun)
the part of a song where a soloist is joined by a group of singers	an organization of musicians who perform together
any utterance produced simultaneously by a group
a group of people assembled to sing together
a body of dancers or singers who perform together
a company of actors who comment (by speaking or singing in unison) on the action in a classical Greek play

chorus (verb)	musical group (verb)
utter in unison
sing in a choir