In theatrical music, a number is a particular piece of music from a larger work such as an opera, cantata, oratorio, musical, or set of incidental music. In colloquial speech, the term number is most often used to refer to a particular song from such a work, but can also be applied to the music played between songs.

This usage comes from the fact that musical segments in a theatrical music score are numbered. This is for convenience and easy reference in rehearsal. (Segments within numbers are lettered.) The numbers were designed to provide a common reference for all the musicians, actors, and crew involved. This solved the difficulty where an "Act I, Scene 5" reference for the actors would leave the pit orchestra out of the loop, a "Semele's da capo aria" would leave the crew out, and "The beginning of the countersubject of the fugato section, please" would leave both the singers and the crew clueless.1

A common system in modern scores is to give major songs or beginnings of scenes their own numbers such as "3" and subsequent related sections or instrumental interludes number-letters such as "3A". An example is this excerpt from the table of contents of the 1956 Candide Broadway score:

1    Ensemble: The Best of All Possible Worlds (Pangloss, Candide, Cunegonde, Chorus)
2    Duet: Oh, Happy We (Candide, Cunegonde)
2A   Chorus and Instrumental: Wedding Procession, Chorale and Battle Scene
3    Instrumental: Candide Begins His Travels
3A   Song: It Must Be So (Candide)
3B   Instrumental: Candide Continues His Travels
In a work that is sung throughout, such as an opera or an oratorio, number-letters are generally not required. For example, this excerpt from Handel's Messiah:
1              Sinfonia (Overture)
2    Recit.    Comfort ye my people
3    Air       Ev'ry valley shall be exalted
4    Chorus    And the glory of the Lord

Small bit of trivia: the famous "Hallelujah Chorus" from Messiah is No. 44.

The use of numbers gave rise to phrases such as "No. 6 from the top" or "Next number, please." Gradually, instead of just being the labels for the music, numbers became the music, so that conductors would say "What about we try your solo number again?" to an unprepared soprano.

Nowadays, the word number has gone past theatrical usage and made its way to the concert stage and the cabaret. One might conceivably ask the cabaret or club singer, "What numbers do you have in store for us today?" or compliment him or her by saying "Your rendition of that number was fantastic." In fact, this word is now in common usage as a general word for any kind of performed song.

And now you know why!


1 That said, when we (the pit) want to keep to ourselves and not have those pesky singers2 bother us, we still like to use phrases such as "the countersubject of the fugato section" or "the first theme in the recapitulation of the overture." Just for fun. ::evil grin::

2 Never "vocalists"—that would imply they know what they're doing. And certainly never "musician." ::shudder::

::laugh:: Okay okay, all in good fun. I sing, myself, and know what's like to be on the other side. And to be fair, there sometimes are good singers—good vocalists—on the stage. And when that happens, it's wonderful.


Handel, G. F.; Charles Jennens; and Watkins Shaw (ed.). Messiah. Vocal Score. The New Novello Choral Edition. Novello Handel Edition. London: Novello & Co. Ltd., 1992.
Hutchins, Michael H. Candide / The 1958 Broadway Score. <>. Accessed 22 January 2005.