1. The use of electromagnetic waves to transmit and receive information, as in sound broadcasts or two-way communication, without the need for connecting wires.
2. Communication that takes place by means of radio waves.
3. An electronic device for receiving sound broadcasts transmitted via radio signals.
4. An electronic device used to send and receive radio signals, used for two-way communications.
5. The broadcasting by radio of programs (news, music, talk shows, etc.) for the public.
6. Radio broadcasting as an industry or profession.