|an electromagnetic wave of radio frequency|
|a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.|
|a gadget; dingus; thingumbob.|
A very low frequency electromagnetic wave (from roughly 30 kilohertz to 100 gigahertz). Radio waves are used for the transmission of radio and television signals; the microwaves used in radar and microwave ovens are also radio waves. Many celestial objects, such as pulsars, emit radio waves. See more at electromagnetic spectrum.