chorus

(noun) any utterance produced simultaneously by a group. Example: "A chorus of boos."

(noun) a group of people assembled to sing together.

(noun) the part of a song where a soloist is joined by a group of singers. Synonyms: refrain.

(noun) a body of dancers or singers who perform together. Synonyms: chorus line.

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

(verb) utter in unison. Example: "`yes,' the children chorused."

(verb) sing in a choir. Synonyms: choir.