rhythm section

A rhythm section includes the musicians in a jazz or popular music band or ensemble who establish the rhythmic pulse of a song or musical piece and lay down the chordal structure. The term "rhythm section" may also refer to the instruments in this group.The core elements of the rhythm section are the drums and a bass instrument (either double bass for Swing or Bebop jazz or a bass guitar for pop, fusion, R&B and funk). Both instruments lay down the pulse for the music, and the bass lays down the harmonic foundation with a bassline. Most groups also use chordal instruments in their rhythm sections, such as rhythm guitar, piano or other keyboard instruments, such as the electric piano, Hammond organ, or vibraphone.
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Noun
1. the section of a band or orchestra that plays percussion instruments
(synonym) percussion section, percussion
(hypernym) section