third rail


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

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,, "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,, "Ask Tom: What year did an ice storm disrupt Easter weekend?," 27 Mar. 2018 Prime Minister Abe deserves credit for touching one of the third rails of Japanese politics. The Editorial Board, WSJ, "Japan Wants Guest Workers," 20 June 2018 Even though there is a literal Nazi movement rising in this country, Hitler is the third rail of every conversation, no matter how apt the comparison. Michael Harriot, The Root, "White People Are Cowards," 19 June 2018 Metro said the Red Line train that broke down at Forest Glen at the height of the afternoon rush Tuesday struck a metal object, resulting in smoke when the object came into contact with the electrified third rail. Faiz Siddiqui, Washington Post, "Red Line single-tracking between Silver Spring and Wheaton Metro stations after train breaks down sending smoke into tunnel," 5 June 2018 The misogynistic term remains the third rail of profanity. Stephanie Ebbert,, "Why the c-word is still the third rail of profanity," 1 June 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

7 Sep 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


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 Encyclopedia article about third rail

Comments on third rail

What made you want to look up third rail? Please tell us where you read or heard it (including the quote, if possible).


the setting in which something occurs

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