0 a musical instrument that is played to provide a strong beat to a piece of music: --
Members of the choir danced in the aisles with tambourines and other rhythm instruments.
He uses his guitar as a supporting rhythm instrument.
Madness was mostly content to keep its horns as rhythm instruments.
The Roland TR-808 drum machine was the rhythm instrument of choice on many early '80s dance records.
He often played bass guitar as a lead rather than rhythm instrument giving The Who their unique sound.