ra·​dio | \ ˈrā-dē-ˌō How to pronounce radio (audio) \

Definition of radio

 (Entry 1 of 4)

1 : of, relating to, or operated by radiant energy
2 : of or relating to electric currents or phenomena (such as electromagnetic radiation) of frequencies between about 3000 hertz and 300 gigahertz
3a : of, relating to, or used in radio or a radio set
b : specializing in radio or associated with the radio industry
c(1) : transmitted by radio
(2) : making or participating in radio broadcasts
d : controlled or directed by radio


plural radios

Definition of radio (Entry 2 of 4)

1a : the wireless transmission and reception of electric impulses or signals by means of electromagnetic waves
b : the use of these waves for the wireless transmission of electric impulses into which sound is converted
2 : a radio message
3 : a radio receiving set
4a : a radio transmitting station
b : a radio broadcasting organization
c : the radio broadcasting industry
d : communication by radio


radioed; radioing; radios

Definition of radio (Entry 3 of 4)

transitive verb

1 : to send or communicate by radio
2 : to send a radio message to

intransitive verb

: to send or communicate something by radio

Definition of radio- (Entry 4 of 4)

— see radi-

Examples of radio in a Sentence

Noun The news was sent by radio. I listen to the radio all the time. I heard the news on the radio. There's a problem with the car's radio. The radio was playing very loudly. The pilot's radio wasn't working. Verb The police radioed for backup. The stranded sailors were radioing for help. The pilot radioed in to the control tower. The police radioed a report back to the station. They radioed the Coast Guard for help.
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Recent Examples on the Web: Noun The tradition continued to gain popularity, leading to the parade eventually being broadcasted over the radio for the first time in 1932 and televised starting in 1952. Selena Barrientos, Good Housekeeping, "Macy's 2019 Thanksgiving Day Parade Has So Many Surprises in Store," 28 Nov. 2019 In a radio interview with Bill O'Reilly that aired Tuesday, Mr. Trump said that tens of thousands of Americans are killed every year because of drug trafficking and other activity by cartels. CBS News, "Trump says he'll designate Mexican drug cartels as terrorist groups," 27 Nov. 2019 Trump, meanwhile, tried to put distance between himself and Giuliani in a radio interview Tuesday. Darlene Superville, Twin Cities, "Trump knew of whistleblower before releasing Ukraine aid," 27 Nov. 2019 Nick Duncan, the hospital’s director of emergency management, got on the radio and dispatched a transport crew to move a patient out and a cleaning crew from upstairs to clean the room. John Diedrich,, "Some busy hospitals say they must turn away ambulances. Here's how one state banned the practice," 22 Nov. 2019 The gown, a collaboration between Christian Siriano and artist Alice Mizrachi, featured two messages, responding to an industrywide discussion about the trouble female stars have getting their music played on country radio stations. Glamour, "All the Best Looks from the 2019 CMA Awards," 14 Nov. 2019 In an Irish radio interview, a cousin says Grace came to New York to find her mother, who had emigrated shortly after her birth. Carmel Mc Mahon, Longreads, "Brigid, Magdalene, My Mother, and Me," 13 Nov. 2019 After Oz’s death, the Israeli Public Broadcasting Corporation, known as Kan, released a number of radio interviews with him from its archives. Gal Koplewitz, The New Yorker, "Amos Oz and the Politics of the Hebrew Language," 12 Nov. 2019 During a radio interview in Minneapolis, Amy Klobuchar addressed the news that Bloomberg was considering seeking the presidency. Caroline Hallemann, Town & Country, "Democratic Candidates React to Michael Bloomberg's Potential Run," 8 Nov. 2019 Recent Examples on the Web: Verb John radioed Dom, who immediately sent us a high-speed Zodiac piloted by a mechanic. Washington Post, "In the Greek islands, a ‘slow travel’ sailing odyssey to the far Ionians," 29 Nov. 2019 McCauley radioed the air traffic controller just five minutes after takeoff to say that the plane was not gaining altitude and there was trouble with the plane’s No. 4 engine. Nicholas Rondinone,, "NTSB releases preliminary report about crash of B-17 at Bradley International Airport," 15 Oct. 2019 Among the 13 onboard were two pilots who radioed the tower about a problem. Kris Van Cleave, CBS News, "World War II-era bomber plane crashes in Connecticut, killing 7," 2 Oct. 2019 After radioing the tower to inform them of the man, the pilots shut the plane’s engine down while officials rushed to the scene. Joelle Goldstein,, "Man Jumps on Plane's Wing and Attempts to Enter the Cabin as Aircraft Prepares for Takeoff," 19 July 2019 Dennison radioed for backup, performing a mental inventory on her weaponry: the Glock 22 . Los Angeles Times, "On a vast reservation, female Navajo officers patrol with bulletproof vests and protective amulets," 13 Aug. 2019 Reinosa radioed for help Wednesday from the police station parking lot, saying he had been shot by a sniper. CBS News, "Los Angeles sheriff's deputy may face criminal charges after allegedly fabricating sniper story," 26 Aug. 2019 The Front Altair, loaded with naphtha from the United Arab Emirates, radioed for help as its cargo of flammable chemicals caught fire. Washington Post, "US says video shows Iran removing mine from stricken tanker," 14 June 2019 The criminal complaint claims that McNeil radioed back to the Coast Guard that there were 10 people on board: himself, Bradford and eight Japanese nationals. Mario Ariza,, "Businessman accused of smuggling a dozen Chinese nationals," 13 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radio.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of radio


1887, in the meaning defined at sense 1


1903, in the meaning defined at sense 1a


1913, in the meaning defined at transitive sense 1

History and Etymology for radio

Noun and Adjective

short for radiotelegraphy

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Time Traveler for radio

Time Traveler

The first known use of radio was in 1887

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Statistics for radio

Cite this Entry

“Radio.” The Dictionary, Merriam-Webster Inc., Accessed 11 December 2019.

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More Definitions for radio



English Language Learners Definition of radio

 (Entry 1 of 2)

: the system or process that is used for sending and receiving signals through the air without using wires
: programs that are broadcast by radio
: a device that is used to receive the signals that are broadcast by radio



English Language Learners Definition of radio (Entry 2 of 2)

: to send a message to someone by radio


ra·​dio | \ ˈrā-dē-ˌō How to pronounce radio (audio) \
plural radios

Kids Definition of radio

 (Entry 1 of 3)

1 : the process that is used for sending or receiving signals by means of electromagnetic waves without a connecting wire
2 : a device that receives signals sent by radio
3 : programs that are broadcast by radio
4 : a device used to both send and receive messages by radio
5 : the radio broadcasting industry



Kids Definition of radio (Entry 2 of 3)

1 : of or relating to radio waves
2 : of, relating to, or used in radio broadcasting


radioed; radioing

Kids Definition of radio (Entry 3 of 3)

: to communicate or send a message to by radio

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More from Merriam-Webster on radio

Rhyming Dictionary: Words that rhyme with radio

Spanish Central: Translation of radio

Nglish: Translation of radio for Spanish Speakers

Britannica English: Translation of radio for Arabic Speakers Encyclopedia article about radio

Comments on radio

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heavy with or as if with moisture

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