Music .

a group of persons singing in unison.

(in an opera, oratorio, etc.) such a group singing choral parts in connection with soloists or individual singers.

a piece of music for singing in unison.

a part of a song that recurs at intervals, usually following each verse; refrain.

simultaneous utterance in singing, speaking, shouting, etc.

the sounds so uttered

a chorus of jeers.

(in a musical show)

a company of dancers and singers.

the singing, dancing, or songs performed by such a company.

(in ancient Greece)

a lyric poem, believed to have been in dithyrambic form, that was sung and danced to, originally as a religious rite, by a company of persons.

an ode or series of odes sung by a group of actors in ancient Greek drama.

the group of actors that performed the chorus and served as major participants in, commentators on, or as a supplement to the main action of the drama.

Theater .

a group of actors or a single actor having a function similar to that of the Greek chorus, as in Elizabethan drama.

the part of a play performed by such a group or individual.

to sing or speak in chorus. ?

in chorus

in unison; with all speaking or singing simultaneously

They responded in chorus to the minister's questions.

noun

carolers , choir , chorale , choristers , ensemble , glee club , singing group , vocalists , voices , bob , burden , main section , melody , motif , music , recurrent verse , response , ritornelle , song , strain , theme , tune , undersong , accord , concert , concord , consonance , harmony , unison , (greek.) , agreement , consensus , echo , refrain