In music, a swung note or shuffle note is a performance practice, mainly in jazz-influenced music, in which some notes with equal written time values are performed with unequal durations, usually as alternating long and short. It follows similar principles to notes inégales of the Baroque and Classical music eras. A swing or shuffle rhythm is the rhythm produced by playing repeated pairs of notes in this way. Lilting can refer to swinging, but might also indicate syncopation or other subtle ways of interpreting and shaping musical time. A blues shuffle or shuffle pattern is a boogie groove.

In shuffle rhythm, the first note in the pair is exactly twice the duration of the second note. In swing the division is inexact, and varies depending on factors such as how fast or slow the music is, on the genre of music, or the individual tastes of the performer, from almost equal (typically at fast tempos) to almost shuffle (typically at slow tempos).

In most styles of music that use swing rhythm, the music is written with straight eighth notes, with an implicit understanding that eighth notes should be played with swing feel.

In jazz, the verb "to swing" is also used as a term of praise for playing that has a strong rhythmic "groove" or drive. See also swing (genre) for the 1930s-1940s jazz style, and swing (dance) for styles of dance from that same era.