ostinato
A short musical pattern repeated persistently throughout a passage.
In Depth
An ostinato is a short musical pattern — melodic, rhythmic, or harmonic — that repeats persistently throughout a passage or entire piece. The repetition creates a hypnotic, grounding effect over which other musical elements can change and develop.
The ground bass or basso ostinato was a favourite Baroque technique: a repeating bass line over which variations unfold. Pachelbel's Canon is built on one of the most famous ostinato bass lines in music. In the 20th century, minimalist composers like Philip Glass and Steve Reich made ostinato patterns the foundation of their entire compositional approach. Riff-based rock music is also essentially ostinato-driven.
Ravel's Boléro is essentially a single 17-minute ostinato — the same rhythm repeats 169 times without variation. Ravel called it an experiment and was surprised it became his most famous work.