The term RADIO USER can be broken down into two parts: HAM (3 letters) and RADIO. HAM is an acronym for 'amateur RADIO, ' which is a type of RADIO communication used by hobbyists and enthusiasts. Amateur RADIO operators, or 'HAMS, ' use their radios to communicate with other HAMS around the world. RADIO refers to the technology used to transmit and receive these signals. RADIO users are those who operate radios for either personal or professional purposes.