Definition of "Chorus" :

noun: the part of a song where a soloist is joined by a group of singers

noun: any utterance produced simultaneously by a group

"A chorus of boos."

noun: a group of people assembled to sing together

noun: a company of actors who comment (by speaking or singing in unison) on the action in a classical Greek play

noun: a body of dancers or singers who perform together

verb: utter in unison

"Yes,' the children chorused."

verb: sing in a choir