"Sideband" refers to the frequency range on both sides of the carrier frequency in radio communications, but there are alternative synonyms that can be used to describe this concept. Words such as "subcarrier," "supplementary channel," or "multiplexed signal" can be used to indicate the extra information being transmitted alongside the main signal. In some contexts, "modulation signal" or "modulation wave" may also be used to describe the sidebands' relationship to the primary signal's carrier wave. Overall, these synonyms all refer to the same idea of additional data being transmitted alongside the primary signal, with the technical terminology varying across different fields and applications.