Which term describes a rhythm that employs two or more different rhythms simultaneously?

The term that describes a rhythm employing two or more different rhythms simultaneously is polyrhythm. In music, polyrhythm creates a rich and complex texture by layering contrasting rhythmic patterns, often found in various musical styles across the world. This technique allows musicians to explore intricate interactions between different beats and sequences, enhancing the overall dynamism of the composition.

Ostinato refers to a repeated musical phrase or rhythm, typically serving as a structural foundation within a piece, rather than the simultaneous layering of distinct rhythms. Cross-rhythm involves a specific type of polyrhythm where two contrasting rhythms are played against each other, often resulting in a noticeable syncopation effect. It is a subset of polyrhythm rather than a stand-alone definition. Rhythmic displacement consists of altering a rhythmic pattern so that its accents are shifted in time, which changes its placement but not necessarily the simultaneous layering aspect.