riff
A short, repeated musical phrase, especially in rock, jazz, and popular music.
In Depth
A riff is a short, catchy, repeated musical figure that serves as the foundation or signature of a song. Unlike an ostinato (which is a classical term for a similar concept), a riff is typically associated with popular music — rock, blues, funk, and jazz.
Some of the most famous moments in popular music are riffs: the opening of Smoke on the Water (Deep Purple), Satisfaction (Rolling Stones), Seven Nation Army (White Stripes), and Day Tripper (Beatles). A great riff is instantly recognisable, rhythmically compelling, and simple enough to remember after one hearing. Many songs are built entirely on a single riff that repeats throughout.
The riff from Smoke on the Water is considered the first thing most beginner guitarists learn — it has introduced more people to guitar playing than any other piece of music.