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• radio
  radio

  noun

  wireless telegraphy or telephony.
• radio-
  radio-

  a combining form with the meanings “dealing with radiant energy” (radiometer ), “employing or dealing with radio waves” (radioacoustics; radiolocation; radiotelephone ), “emitting rays as a result of the breakup of atomic nuclei” (radioactive; radiocarbon ), “characterized by, employing or dealing with such rays” (radiography; radiopaque; radiotherapy ).

radio

¹ American  

[rey-dee-oh] / ˈreɪ diˌoʊ /

noun

plural

radios

1. wireless telegraphy or telephony.

   speeches broadcast by radio.

2. an apparatus for receiving or transmitting radio broadcasts.

3. a message transmitted by radio.

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adjective

1. pertaining to, used in, or sent by radio.

2. pertaining to or employing radiations, as of electrical energy.

verb (used with object)

radioed, radioing

1. to transmit (a message, music, etc.) by radio.

2. to send a message to (a person) by radio.

verb (used without object)

radioed, radioing

1. to transmit a message, music, etc., by radio.

radio- ² American  

1. a combining form with the meanings “dealing with radiant energy” (radiometer ), “employing or dealing with radio waves” (radioacoustics; radiolocation; radiotelephone ), “emitting rays as a result of the breakup of atomic nuclei” (radioactive; radiocarbon ), “characterized by, employing or dealing with such rays” (radiography; radiopaque; radiotherapy ).

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radio ¹ British  

/ ˈreɪdɪəʊ /

noun

1. the use of electromagnetic waves, lying in the radio-frequency range, for broadcasting, two-way communications, etc

2. Also called (esp Brit): wireless.  an electronic device designed to receive, demodulate, and amplify radio signals from sound broadcasting stations, etc

3. a similar device permitting both transmission and reception of radio signals for two-way communications

4. the broadcasting, content, etc, of sound radio programmes

   he thinks radio is poor these days

5. 1. the occupation or profession concerned with any aspect of the broadcasting of sound radio programmes

      he's in radio

   2. (modifier) relating to, produced for, or transmitted by sound radio

      radio drama

6. short for radiotelegraph radiotelegraphy radiotelephone

7. (modifier)

   1. of, relating to, employed in, or sent by radio signals

      a radio station

   2. of, concerned with, using, or operated by radio frequencies

      radio spectrum

8. (modifier) (of a motor vehicle) equipped with a radio for communication

   radio car

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verb

1. to transmit (a message) to (a person, radio station, etc) by means of radio waves

radio- ² British  

combining form

1. denoting radio, broadcasting, or radio frequency

   radiogram

2. indicating radioactivity or radiation

   radiochemistry

   radiolucent

3. indicating a radioactive isotope or substance

   radioactinium

   radiothorium

   radioelement

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radio Scientific  

/ rā′dē-ō /

1. The equipment used to generate, alter, transmit, and receive radio waves so that they carry information.

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1. Relating to or involving the emission of radio waves.

Other Word Forms

• preradio
  adjective

Etymology

Origin of radio¹

1910–15; shortening of radiotelegraph or radiotelegraphy

Origin of radio-²

< French, combining form representing Latin radius beam, ray, radius

Explanation

Radio is a way of transmitting sound using electromagnetic waves called radio waves. Nowadays, people usually only listen to the radio as they drive, but — before television — radio provided prime-time entertainment. When you turn on your car radio, you probably take for granted the many choices of music and talk stations you can choose from. The radio's electronic components do the amazing job of catching fast-moving radio waves in the air and translating them into sounds you can hear. Radios were originally called wireless because they transmit energy using waves instead of wires. The Latin root of radio is radius, "beam."

Example Sentences

Instead of producing a standard image of brain structure, 1H-MRS uses magnetic fields and radio waves to measure chemical levels in tissue.

From Science Daily • May 16, 2026

Follow live text commentary plus TV and radio coverage on the BBC Sport website and app.

From BBC • May 15, 2026

I can see that song finding its legs on rap radio along with — hey, whaddya know?

From Los Angeles Times • May 15, 2026

Wall Street seems worried about Intel’s P/E radio of 94 times earnings expected over the coming 12 months, which dwarfs the 28 P/E of the iShares Semiconductor ETF.

From Barron's • May 14, 2026

Going radio silent so I my phone doesn’t embarrass me!!!!!!

From "Bye Forever, I Guess" by Jodi Meadows

Related Words

• transmission
• wireless