third rail

noun

Definition of third rail 

1 : a metal rail through which electric current is led to the motors of an electric vehicle (such as a subway car)

2 : a controversial issue usually avoided by politicians

Examples of third rail in a Sentence

Social Security is the third rail of American politics.

Recent Examples on the Web

One of the nation's most combustible issues, race is a third rail for major corporations, which must appeal to a diverse array of customers. Jessica Guynn, USA TODAY, "ABC's move to ax 'Roseanne' reflects businesses are often at front lines of culture wars," 30 May 2018 Arcing on a track happens when stray electrical current from the rail’s third rail finds another path to the ground, usually because of puddled water, mud or dirt. Dana Hedgpeth, Washington Post, "Metro had ‘multiple’ arcing insulators on its Red Line this morning," 12 Jan. 2018 But natural gas is a third rail of Massachusetts politics, and House leaders steered clear. Jon Chesto, BostonGlobe.com, "Mass. lawmakers wrap up work on energy legislation," 13 July 2018 Throughout it all, the deer escaped injury, avoiding contact with the electrified third rail or a train before fleeing out the tunnel. Fox News, "Frankly deer, the Metro station is no place for gallivanting," 12 June 2018 Mario Diaz-Balart and Carlos Curbelo failed to navigate the third rail of GOP politics that has tripped up lawmakers like Florida Sen. Marco Rubio in the past. Alex Daugherty, miamiherald, "Immigration bill brokered by Miami Republicans fails," 27 June 2018 Metro’s central control staff cut power to the third rail and maintenance staff were sent out to remove the fastener. Dana Hedgpeth And Faiz Siddiqui, Washington Post, "Normal service resumes on Metro’s Blue and Yellow lines after track fire at Pentagon City," 7 Mar. 2018 The vehicle toppled over, damaging the electrified third rail that powers subway cars, as well as some additional track equipment. Adam Vaccaro, BostonGlobe.com, "A maintenance vehicle, of all things, shut down the Red Line on Tuesday," 20 June 2018 The city's rapid transit lines were shut down for the first time in 20 years as ice covered the electrified third rail. Tom Skilling, chicagotribune.com, "Ask Tom: What year did an ice storm disrupt Easter weekend?," 27 Mar. 2018

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

1867, in the meaning defined at sense 1

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Last Updated

16 Nov 2018

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Time Traveler for third rail

The first known use of third rail was in 1867

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More Definitions for third rail

third rail

noun

English Language Learners Definition of third rail

: a metal rail on a train track that carries electric current to the train's motor

: a difficult issue that politicians try to avoid talking about

More from Merriam-Webster on third rail

See words that rhyme with third rail

Britannica.com: Encyclopedia article about third rail

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