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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 ).
Synonyms

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.


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 ).


radio- 1 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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

radio 2 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

    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

  5. short for radiotelegraph radiotelegraphy radiotelephone

  6. (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

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

    radio car

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
radio Scientific  
/ rādē-ō /
  1. The equipment used to generate, alter, transmit, and receive radio waves so that they carry information.


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

Other Word Forms

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."

Keep Reading on Vocabulary.com

Vocabulary lists containing radio

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The stolen track chases him everywhere: on the radio, overheard at the mall, even at his own gigs where newlyweds cluelessly ask him to play “their” special song.

From Los Angeles Times • May 28, 2026

In 1973, he joined the cast on Don Imus’s “Imus in the Morning” syndicated radio show, creating characters and doing impersonations.

From The Wall Street Journal • May 26, 2026

Its order book stands at 23.1 million U.S. dollars as of FY 2026, but more orders are expected from its inter-satellite data relay system and advanced digital radio system segments, the analyst says.

From The Wall Street Journal • May 26, 2026

"Obviously when you listen to some of the radio comms, I think there is room for improvement," said Wolff.

From BBC • May 25, 2026

“Earthquake … shakin’,” Gerry reported over his ham radio at 8:32 a.m.

From "Mountain of Fire" by Rebecca E. F. Barone

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