chorus

A chorus is a group of singers or a refrain in a song. (noun)

See chorus in Webster's New World College Dictionary

noun

in ancient Greek drama, and drama like it, a company of performers whose singing, dancing, and narration provide explanation and elaboration of the main action
in Elizabethan drama, a person who recites the prologue and epilogue
a group of dancers and singers performing together in a modern musical show, opera, etc.
the part of a drama, song, etc. performed by a chorus
a group of people trained to sing or speak something together simultaneously
a simultaneous utterance by many: a chorus of protest
that which is thus uttered
music written for group singing
that part of a musical composition in which the company joins the solo singer
1. the refrain of a song or hymn following each verse
2. the main tune, as of a jazz piece, following the introduction
3. Jazz a solo, usually an improvised one based on the main tune of a piece

transitive verb, intransitive verb

to sing, speak, or say in unison

See chorus in American Heritage Dictionary 4

(kôrˈəs, kōrˈ-)

noun pl. cho·rus·es

Music
a. A composition usually in four or more parts written for a large number of singers.
b. A refrain in which others, such as audience members, join a soloist in a song.
c. A line or group of lines repeated at intervals in a song.
d. A solo section based on the main melody of a popular song and played by a member of the group.
e. A body of singers who perform choral compositions, usually having more than one singer for each part.
f. A body of vocalists and dancers who support the soloists and leading performers in operas, musical comedies, and revues.
a. A group of persons who speak or sing in unison a given part or composition in drama or poetry recitation.
b. An actor in Elizabethan drama who recites the prologue and epilogue to a play and sometimes comments on the action.
a. A group of masked dancers who performed ceremonial songs at religious festivals in early Greek times.
b. The group in a classical Greek drama whose songs and dances present an exposition of or, in later tradition, a disengaged commentary on the action.
c. The portion of a classical Greek drama consisting of choric dance and song.
A group or performer in a modern drama serving a purpose similar to the Greek chorus.
The performers of a choral ode, especially a Pindaric ode.
a. A speech, song, or other utterance made in concert by many people.
b. A simultaneous utterance by a number of people: a chorus of jeers from the bystanders.
c. The sounds so made.