A form of electromagnetic radiation traveling at the speed of light whose frequency lies between about 10 kilohertz and about 100,000 megahertz.

Radio waves are low frequency and, therefore, long wavelength electromagnetic radiations.

The radio part of the electromagnetic spectrum lies beyond the infrared region and comprises all radiation with a frequency lower than about 300,000 million hertz (300,000 MHz) or with a wavelength longer than about one millimeter.