In music, a riff is an ostinato figure: a repeated chord progression, pattern, refrain or melodic figure, often played by the rhythm section instruments or solo instrument, that forms the basis or accompaniment of a musical composition (though they are most often found in rock music, Latin, funk and jazz). Classical music is also sometimes based on a simple riff, such as Ravel's Boléro. Riffs can be as simple as a tenor saxophone honking a simple, catchy rhythmic figure, or as complex as the riff-based variations in the head arrangements played by the Count Basie Orchestra.
David Brackett (1999) defines riffs as "short melodic phrases," while Richard Middleton (1999) defines them as, "short rhythmic, melodic, or harmonic figures repeated to form a structural framework." Rikky Rooksby (2002, p.6-7) states that "A riff is a short, repeated, memorable musical phrase, often pitched low on the guitar, which focuses much of the energy and excitement of a rock song."
Charlie Parker's 1945 recording "Thriving on a Riff" brought the term to more popular awareness.
The etymology of the term is not clearly known. Some sources explain riff as an abbreviation for "rhythmic figure" or "refrain" (). The term is also used in a similar sense in comedy where riffing may be the verbal exploration of a particular subject. Thus riffing on a melody or progression as one would riff on a subject by extending a singular thought, idea or inspiration into a bit, or routine.
The riff from Charlie Parker's bebop number "Now's the Time" (1945) re-emerged four years later as the R&B dance hit, "The Hucklebuck". The verse of "The Hucklebuck", which was another riff, was "borrowed" from the Artie Matthews composition, "Weary Blues". Glenn Miller's "In the Mood" had an earlier life as Wingy Manone's "Tar Paper Stomp". All these songs use twelve bar blues riffs, and most of these riffs probably precede the examples given.
Neither the term riff or lick are used in Classical music; instead, individual musical phrases used as the basis of classical music pieces are called ostinatos or simply phrases. Contemporary jazz writers also use riff- or lick-like ostinatos in modal music and Latin jazz.