Ad Libitum - Music or Rhythm

Music or Rhythm

As a direction in sheet music, ad libitum indicates that the performer or conductor has one of a variety of types of discretion with respect to a given passage:

• to play the passage in free time rather than in strict or "metronomic" tempo (a practice known as rubato when not expressly indicated by the composer);
• to improvise a melodic line fitting the general structure prescribed by the passage's written notes or chords;
• to omit an instrument part, such as a nonessential accompaniment, for the duration of the passage; or
• in the phrase "repeat ad libitum," to play the passage an arbitrary number of times (cf. vamp).

Note that the direction a piacere (see above) has a more restricted meaning, generally referring to only the first two types of discretion. Baroque music, especially, has a written or implied ad libitum, with most composers intimating the freedom the performer and conductor have.

For post-Baroque classical music and jazz, see cadenza.