The term "riff" is sometimes regarded as slang, and is used primarily in discussion of forms of rock music or jazz. "Most rock musicians use 'riff' as a synonym, almost, for 'musical idea.'" (Middleton 1990, p.125)
David Brackett (1999) defines them as, "short melodic phrases," while Richard Middleton (1999) defines them as, "short rhythmic, melodic, or harmonic figures repeated to form a structural framework."
A great many rock songs, and nearly all heavy metal music, are formed from a structure of guitar riffs.
The term "riff" is sometimes regarded as slang, and is used primarily in discussion of forms of rock music or jazz.
Some sources explain "riff" as an abbreviation for "rhythmic figure", however, the musical use of the term derives from its use in comedy where a riff is a short clever remark ([1]) on a subject.