1. An assortment of gear that might include speakers, amplifiers, equalizers, mixers, and various ancillary gear used to provide foldback or sound for musicians to hear onstage. See also “stage monitor.”
2. An assortment of gear that might include speakers, amplifiers, equalizers, mixers, and various ancillary gear that provides sound for the engineer, producer, musicians, and others to hear in the control room of a recording studio. See also “studio monitor.”