third rail

[thurd reyl]

SEE MORE SYNONYMS FOR third rail ON THESAURUS.COM

noun

Railroads.

a rail laid parallel and adjacent to the running rails of an electrified railroad to provide electric current to the motors of a car or locomotive through contact shoes.
an additional running rail laid on the same ties as the two regular rails of a railroad track to provide a multigauge capability.

a controversial topic or issue in the public sphere that people, especially politicians, try to avoid discussing (often used attributively): a third-rail subject;Doping is the third rail of the Olympics.Social Security is the third rail of American politics.

Origin of third rail

An Americanism dating back to 1865–70

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for third rail

pantograph

Examples from the Web for third rail

Contemporary Examples of third rail

And then there is the third-rail issue that is particularly electric in a state with so many retirees.
Florida Raises the Ante for 2012
Kirsten Powers
October 8, 2011
Marriage equality is not remotely the third-rail issue it is sometimes considered.
Andrew Cuomo Renews Push for Gay Marriage in New York
John Avlon
June 12, 2011

Historical Examples of third rail

They had traveled by the third-rail line twenty miles into the country.
The Crystal Ball
Roy J. Snell
He may perfect a third-rail system for use on moving trains.
The History of the Telephone
Herbert N. Casson
It was originally on the third-rail system, but was changed into an ordinary overhead trolley seven or eight years ago.
One Irish Summer
William Eleroy Curtis
A great rate of speed can be gained with the third-rail system, ten miles having been made in thirteen and a half minutes.
The Great Round World and What Is Going On In It, Vol. 1, No. 32, June 17, 1897
Various
The third-rail system in its simplest form is shown in Fig. 29, which represents a section through the roadbed.
Appletons' Popular Science Monthly, Vol. 56, March 1900
Various

British Dictionary definitions for third rail

third rail

noun

an extra rail from which an electric train picks up current by means of a sliding collector to feed power to its motors

US politics

a cause or topic that is considered extremely dangerous for a person to support or comment on
(as modifier)a third-rail issue

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Idioms and Phrases with third rail

third rail

Something that is dangerous to tamper with, as in Anything concerning veterans is a political third rail. This term alludes to the rail that supplies the high voltage powering an electric train, so called since 1918. On the other hand, grab hold of the third rail means “become energized.” Both shifts from the original meaning date from the late 1900s.