also side band
sideband - Computer Definition
The band of frequencies, above or below the carrier, created by the process of modulation. The sidebands have considerable value in certain transmission techniques, such as single sideband (SSB), double sideband (DSB), and vestigial sideband (VSB). See also carrier, DSB, frequency, modulate, SSB, and VSB.
In radio communications, a signal that results from amplitude modulating a carrier frequency. The upper sideband is the carrier plus modulation, and the lower sideband is the carrier minus modulation, which are mirror images of each other. See single sideband.