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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

radios plural

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)

radios, present (3rd person singular) radioed, past participle, past radioing present participle

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

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

verb (used without object)

radios, present (3rd person singular) radioed, past participle, past radioing present participle

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

Derived Forms

• preradio
  adjective

Inflected Forms

Nouns

• radios
  plural

Participles

• radioing
  present
• radioed
  past

Conjugated Forms

Present

• radio
  simple
• radios
  simple
• have radioed
  perfect
• has radioed
  perfect
• am radioing
  progressive
• are radioing
  progressive
• is radioing
  progressive
• have been radioing
  perfect progressive
• has been radioing
  perfect progressive

Past

• radioed
  simple
• had radioed
  perfect
• was radioing
  progressive
• were radioing
  progressive
• had been radioing
  perfect progressive

Future

• will radio
  simple
• will have radioed
  perfect
• will be radioing
  progressive
• will have been radioing
  perfect progressive

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

There will also be live radio commentary on BBC Radio 5 Live and BBC Sounds, alongside live text coverage and in-match clips across the BBC Sport website and app.

From BBC • Jul. 3, 2026

"I think Spain have got more gears to go through," former England striker Dion Dublin said on BBC Radio 5 live.

From BBC • Jul. 2, 2026

This week, veteran National Public Radio reporter Nina Totenberg briefly published a story stating that Supreme Court Justice Samuel Alito was retiring.

From Slate • Jul. 2, 2026

"The details are quite closely guarded, but it will travel through the tunnel," Cullinan told BBC Radio 4, referring to the Channel tunnel that connects the UK and France.

From Barron's • Jul. 1, 2026

Radio: it ties a million ears to a single mouth.

From "All the Light We Cannot See" by Anthony Doerr

Related Words

• transmission
• wireless