sem·​a·​phore | \ ˈse-mə-ˌfȯr \

Definition of semaphore

 (Entry 1 of 2)

1 : an apparatus for visual signaling (as by the position of one or more movable arms)
2 : a system of visual signaling by two flags held one in each hand


semaphored; semaphoring

Definition of semaphore (Entry 2 of 2)

transitive verb

: to convey (information) by or as if by semaphore

intransitive verb

: to send signals by or as if by semaphore

Illustration of semaphore

Illustration of semaphore


semaphore 2: alphabet; 3 positions following Z: error, end of word, numerals follow; numerals 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 same as A through J

In the meaning defined above

Examples of semaphore in a Sentence

Recent Examples on the Web: Noun

At their disposal are agreed-upon symbols and semaphores. Rick Paulas, Popular Mechanics, "The Graffiti That Will Save Your Life," 22 Feb. 2016 Customers should be advised to bring semaphores in order to gain the attention of the waitstaff, which seems unaccustomed to any action at all and slightly bemused to encounter actual humans in their midst. Fox, Town & Country, "A Table for Mr. Fox," 21 Nov. 2012 At one point, six of them line up front to back and do a kind of semaphore. Jeffrey Gantz,, "Boston Ballet opens with high-octane ‘Parts in Suite’," 11 Mar. 2018 Aquatic extinctions happen silently, beneath the surface, lacking any clear semaphore. Nick Pyenson, Smithsonian, "There Are Possibly Only 30 of These Rare Porposies Left on the Planet," 26 Oct. 2017 When inflated, they can also be used as fishing bobbers or signaling devices for semaphore, according to SensiblePrepper. Alex Williams, New York Times, "How to Survive the Apocalypse," 23 Sep. 2017 Some towns used a clockwork device with no lights at all, while others used the semaphore system, with Stop and Go placards rotating in and out of a housing like mechanical arms. Bob Sorokanich, Car and Driver, "Traffic Signals Were a Flippin’ Mess in the 1930s [Video]," 20 Sep. 2017 The badge covers topics such as semaphore, American Sign Language, Morse code and the use of nautical flags. Christopher Mele, The Seattle Times, "One Boy Scout has enough merit badges for a whole troop," 23 June 2017 The badge covers topics such as semaphore, American Sign Language, Morse code and the use of nautical flags. Christopher Mele, The Seattle Times, "One Boy Scout has enough merit badges for a whole troop," 23 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'semaphore.' 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 semaphore


1815, in the meaning defined at sense 1


1838, in the meaning defined at transitive sense

History and Etymology for semaphore


Greek sēma sign, signal + International Scientific Vocabulary -phore

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Statistics for semaphore

Last Updated

23 Nov 2018

Look-up Popularity

Time Traveler for semaphore

The first known use of semaphore was in 1815

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More Definitions for semaphore



English Language Learners Definition of semaphore

: a system used for sending signals by using two flags that are held in your hands


sem·​a·​phore | \ ˈse-mə-ˌfȯr \

Kids Definition of semaphore

1 : a device for sending signals that can be seen by the receiver
2 : a system of sending signals with two flags held one in each hand

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More from Merriam-Webster on semaphore

Rhyming Dictionary: Words that rhyme with semaphore

Spanish Central: Translation of semaphore

Nglish: Translation of semaphore for Spanish Speakers Encyclopedia article about semaphore

Comments on semaphore

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someone who never drinks alcohol

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