What is the primary function of an ostinato in a musical piece?

The primary function of an ostinato in a musical piece is to provide a repetitive foundation. An ostinato is a musical phrase or rhythm that is persistently repeated throughout a composition, serving as a stable backdrop over which melodies or variations can develop. This repetition creates a sense of continuity and helps to anchor the listener's attention, allowing other musical elements to interact with the consistent pattern.

In many musical styles, such as classical, jazz, and popular music, the ostinato can support melodies or variations that emerge above it, creating a rich texture. By establishing a strong, recognizable rhythmic or melodic pattern, the ostinato enables composers and performers to explore creativity and improvisation while maintaining a cohesive sound.