ra·dio | \ˈrā-dē-ˌō \

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


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.


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

One of the biggest differences between the college and pro games is NFL teams’ ability to use a headset in one player’s helmet to radio in play calls. Andy Staples,, "Like It or Not, College Football Is Influencing the NFL," 12 July 2018 Emilio, frustrated that stations won’t play their songs, sends the band into the streets with giveaway copies and, moments later, the group is heard playing on a radio. Daryl H. Miller,, "Review: 'On Your Feet!,' the Gloria and Emilio Estefan story, sets rhythms in irresistible motion," 11 July 2018 Schultz started his broadcast career as a radio and TV personality in Fargo, North Dakota, in the 1980s. Anita Bennett, Fortune, "Ed Schultz, Political Commentator and Former MSNBC Host, Dies at 64," 5 July 2018 There's also a radio broadcast of the music on 1010 WINS. Jennifer Aldrich, Country Living, "Here's How to Watch Macy’s 4th of July Fireworks," 3 July 2018 The Pilot Station mayor, Abraham Kelly, said calls for help went out on the village radio. Alex Demarban, Anchorage Daily News, "‘It’s just my job’: Village police, others rescue young family from burning house in Pilot Station," 2 July 2018 While Rodriguez isn’t feeling much pressure, Mendoza is still forced to carry the weight on her shoulders of being the league’s sole female television analyst (Suzyn Waldman has been calling Yankee games on the radio since 2005). Rob Tornoe,, "ESPN's Alex Rodriguez candid ahead of calling Phillies 'Sunday Night Baseball' game: 'I stink'," 23 June 2018 The Judases formerly known as the Chargers ARE on radio here. Nick Canepa,, "Justify’s Triple Crown win huge, in light of greats who fell short," 9 June 2018 An additional $250,000 of the funding will be allocated for public education, including television and radio spots in both English and Spanish. Bree Burkitt, azcentral, "Latest string of deadly pedestrian accidents continues Arizona trend," 2 July 2018

Recent Examples on the Web: Verb

Craig Chapman radioed the Sky Harbor tower, asking for police backup. Ashleigh R Wilson, azcentral, "Yes, it really happened on an airport tarmac in metro Phoenix," 29 July 2016 However, the No. 2 Ford struggled on a long green-flag run late in the race and fell two laps behind after radioing in that something broke in his suspension. Fox News, "Kyle Busch wins rain-delayed Bristol NASCAR race," 16 Apr. 2018 Politi said the most common way for sharks to be detected along the Cape is by spotters in planes who radio the sightings to the various harbor masters, who then relay the news to on-duty lifeguards and beach patrol personnel. Sophia Eppolito And Marek Mazurek,, "On the Cape, tourists and locals take sharks in stride," 9 July 2018 And according to a $96,000 Southwest Research Institute study commissioned by the city, Motorola radios function better under firefighting conditions. Josh Baugh, San Antonio Express-News, "Council members lobbied ahead of radio vote," 13 Feb. 2018 Police on the scene Wednesday night in Chicago radioed that thousands of people sought shelter under a bridge on Lake Shore Drive. Alicia Fabbre, Elgin Courier-News, "'I felt the shock': St. Charles fire captain, Plainfield paramedic credited with saving lives of 2 lightning strike victims," 6 July 2018 In 1965, Cohen was caught radioing information to Israel. Aron Heller, Fox News, "Israel's Mossad spy agency shrouded in mystery and mystique," 1 May 2018 At a cornfield near Granjeno, Texas, Medina abruptly parked his car and ran into the muddy rows of corn stalks after the suspect, as a Marine helicopter circled overhead and radioed the suspect's location. Rick Jervis, USA TODAY, "'It's a game of hide-and-seek': A look at how Border Patrol apprehends illegal immigrants," 21 June 2018 In Thursday's exercise, the first four officers had to find one another, radio their situation and work their way through the building, stalking after the gun blasts that trainers fired from airguns. Joe Robertson, kansascity, "Making terror real: Police active-shooter training is meant to overwhelm | The Kansas City Star," 15 Mar. 2018

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


radio entry 2 or radio-


short for radiotelegraphy

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Statistics for radio

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Time Traveler for radio

The first known use of radio was in 1887

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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 \
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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Comments on radio

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lying above or upon

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