rhythm section
The instruments that provide the rhythmic and harmonic foundation: typically drums, bass, piano, and guitar.
In Depth
The rhythm section is the engine room of a band or ensemble, providing the beat, the bass line, and the harmonic framework over which soloists and vocalists perform. In jazz, the standard rhythm section is piano, bass, and drums. In rock and pop, it is typically drums, bass, and rhythm guitar (sometimes with keyboards).
The rhythm section must be tight — locked together in tempo and feel — while remaining flexible enough to respond to what the soloists are doing. The interaction between bassist and drummer is particularly critical: they share responsibility for the groove. Great rhythm sections (like Motown's Funk Brothers or the Beatles' rhythm section of McCartney and Starr) become legendary for their collective feel.
Motown's house rhythm section, the Funk Brothers, played on more number-one hits than the Beatles, Rolling Stones, Beach Boys, and Elvis combined — yet they remained virtually unknown until a 2002 documentary.