Ostinato

Ostinato, an Italian word meaning "stubborn" (compare English obstinate), is to classical music what riffs are to popular music.

An ostinato is a bit of melody, a chord progression, or a bass figure that is repeated over and over at the same pitch. Ostinato is frequently used in Baroque music, where the basso continuo invites the use of the technique, and fixed forms such as the passacaglia and the chaconne require it. The left hand in boogie woogie piano playing is another.

See also Alberti bass.