A melodic ostinato is a pattern of notes, rhythms or movements that persistently repeats in a piece of music. The ostinato accompanies the melody. The word stems from the Italian for "stubborn," and it is typically pluralized as ostinati.
A melodic ostinato provides a musical piece with polymorphic texture. The ostinato is a melodic voice being performed with another melody. In that way, it is similar to countermelodies, partner songs and rounds. However, the melodic ostinato consists of repeating patterns of notes, usually in the same pitch.
Traditionally, ostinati consist of exact repetition. However, in modern usage of the device, variation and development are acceptable. For instance, a line within the ostinato can be changed to fit altered harmonies and keys.
Melodic ostinato is a centerpiece of improvised music, especially jazz and rock. It is also common in African, boogie-woogie and Gnawa music. A famous piece of classical music with melodic ostinato is "Bolero" by Maurice Ravel. Other famous classical works with ostinati include Igor Stravinsky's introduction to "The Rite of Spring" and the end of the second scene in Wolfgang Amadeus Mozart's "Marriage of Figaro."
In 20th-century classical music, composers often used ostinati to stabilize the pitch in different groups. For instance, one type of ostinato is the Rossini crescendo. In this usage, the crescendo underlies the repeating pattern of notes. Another example is using ground bass as a repeating rhythmic accompaniment to the melodic theme of a piece.