Sheet music is a hand-written or printed form of musical notation; like its analogs—books, pamphlets, etc.—the medium of sheet music typically is paper (or, in earlier times, parchment), although the access to musical notation in recent years includes also presentation on computer screens. Use of the term "sheet" is intended to differentiate music on paper from an audio presentation, which would ensue from a sound recording, broadcast, or live performance, which may involve video as well. In everyday use, "sheet music" (or simply "music") can refer to the print publication of commercial music in conjunction with the release of a new film, show, record album, or other special or popular event which involves music.

Score is a common alternative (and more generic) term for sheet music, and there are several types of scores, as discussed below. (Note: the term score can also refer to incidental music written for a play, television programme, or film; for the last of these, see film score.)

Purpose and use

Sheet music can be used as a record of, a guide to, or a means to perform, a piece of music. Although it does not take the place of the sound of a performed work, sheet music can be studied to create a performance and to elucidate aspects of the music that may not be obvious from mere listening. Authoritative musical information about a piece can be gained by studying the written sketches and early versions of compositions that the composer might have retained, as well as the final autograph score and personal markings on proofs and printed scores.

Comprehending sheet music requires a special form of literacy: the ability to read musical notation. Nevertheless, an ability to read or write music is not a requirement to compose music. Many composers have been capable of producing music in printed form without the capacity themselves to read or write in musical notation—as long as an amanuensis of some sort is available. Examples include the blind 18th-century composer John Stanley and the 20th-century composers and lyricists Lionel Bart, Irving Berlin and Paul McCartney.

The skill of sight reading is the ability of a musician to perform an unfamiliar work of music upon viewing the sheet music for the first time. Sight reading ability is expected of professional musicians and serious amateurs who play classical music and related forms. An even more refined skill is the ability to look at a new piece of music and hear most or all of the sounds (melodies, harmonies, timbres, etc.) in one's head without having to play the piece.

With the exception of solo performances, where memorization is expected, classical musicians ordinarily have the sheet music at hand when performing. In jazz music, which is mostly improvised, sheet music—called a lead sheet in this context—is used to give basic indications of melodies, chord changes, and arrangements.