radio

Etymology

Short for radiotelegraphy.

noun

1. (uncountable) The technology that allows for the transmission of sound or other signals by modulation of electromagnetic waves.
   send a message by radio
2. (countable) A device that can capture (receive) the signal sent over radio waves and render the modulated signal as sound.
   We heard a lovely song on the radio.
3. (countable) On-board entertainment system in a car, usually including a radio receiver as well as the capability to play audio from recorded media.
   David Bowie's classic hit Space Oddity will be looping on the radio as the car is hurled into an elliptical orbit that stretches out to Mars' orbit around the Sun. 2018-02-06, Jonathan Amos, “Elon Musk's huge Falcon Heavy rocket set for launch”, in BBC News, London, United Kingdom: BBC, retrieved 2018-02-07
4. (countable) A device that can transmit radio signals.
5. (Internet, uncountable) The continuous broadcasting of sound via the Internet in the style of traditional radio.

verb

1. (transitive, intransitive) To use two-way radio to transmit (a message) (to another radio or other radio operator).
   I think the boat is sinking; we'd better radio for help. / I radioed him already. / Radio the coordinates this time. / OK. I radioed them the coordinates.
2. (transitive) To order or assist (to a location), using telecommunications.
   “Could you call them here? I'd like to talk to them. Or if they're out in the field, radio them in.” 2002, Jack Dave, Death Bridge, iUniverse, page 40
   When I told him that they weren't back yet, he asked if we could radio them back early […] Radioing them in was fine with me. 2006, Angie Morgan, Courtney Lynch, Leading from the front: no excuse leadership tactics for women, page 111
   When she arrived, she was told that Tad wasn't there and to have a seat and wait while they radioed him in. 2006, Kimberly Johnson, Amy's Secret, page 14