third rail

noun
|Updated on: 15 Jun 2018

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

  1. Social Security is the third rail of American politics.

Recent Examples of third rail from the Web

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.

First Known Use of third rail

1867

in the meaning defined at sense 1

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THIRD RAIL Defined for English Language Learners

third rail

Definition of third rail for English Language Learners

  • : 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


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