litmus test

noun

Definition of litmus test

: a test in which a single factor (such as an attitude, event, or fact) is decisive

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Litmus Test Has Scientific Origins

It was in the 14th century that scientists discovered that litmus, a mixture of colored organic compounds obtained from lichen, turns red in acid solutions and blue in alkaline solutions and, thus, can be used as an acid-base indicator. Six centuries later, people began using litmus test figuratively. It can now refer to any single factor that establishes the true character of something or causes it to be assigned to one category or another. Often it refers to something (such as an opinion about a political or moral issue) that can be used to make a judgment about whether someone or something is acceptable or not.

Examples of litmus test in a Sentence

The party is using attitudes about gun control as a litmus test for political candidates.

Recent Examples on the Web

McMaster has tried to make Trump a litmus test, noting that his opponent supported Sen. Ted Cruz of Texas in the 2016 presidential primary. Time, "President Trump Urges South Carolina to Vote for Gov. Henry McMaster," 25 June 2018 The onetime insurgent has made allegiance to his leadership a litmus test in many Republican races. John Whitesides, The Christian Science Monitor, "Pro-Trump challenger topples Rep. Mark Sanford in South Carolina primary," 13 June 2018 Free college is quickly emerging as a litmus test for Democratic contenders. Steve Peoples, The Seattle Times, "Democrats lurch left on top policies as 2020 primary begins," 22 Jan. 2019 And in laying out his complaints about the Iran deal in such detail, Trump set an incredibly onerous litmus test that any forthcoming pact with North Korea must now ostensibly pass. Washington Post, "Analysis: Trump taking opposite approaches to Iran, NKorea," 9 May 2018 Landing just days after hundreds of local companies issued profit warnings and multinationals sounded the alarm about softening demand, the week-long Lunar New Year holiday will provide the next litmus test of the resilience of the Chinese shopper. Daniela Wei, The Seattle Times, "Lunar New Year will show trade war’s effects in China economy," 4 Feb. 2019 What started as crank progressive politics is becoming a litmus test for 2020 Democratic presidential aspirants. The Editorial Board, WSJ, "The Drug Price-Control Threat," 8 Jan. 2019 Sanford, a former South Carolina governor, blamed his loss on Trump, saying that support for the president is becoming a litmus test in GOP primaries. Nicole Darrah, Fox News, "Trump says House GOP 'applauded and laughed loudly' after Sanford reference, despite claims of booing," 21 June 2018 Support for this basic premise — that corruption is fine so long as the right people are doing it — is fast becoming a litmus test for ideological purity on the American right. Eric Levitz, Daily Intelligencer, "Pro-Trump EPA Official: Pruitt Asked Us to Rent Him a Private Plane," 12 Apr. 2018

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

1913, in the meaning defined above

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Last Updated

13 Mar 2019

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The first known use of litmus test was in 1913

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More Definitions for litmus test

litmus test

noun

English Language Learners Definition of litmus test

: something (such as an opinion about a political or moral issue) that is used to make a judgment about whether someone or something is acceptable

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More from Merriam-Webster on litmus test

Thesaurus: All synonyms and antonyms for litmus test

Spanish Central: Translation of litmus test

Nglish: Translation of litmus test for Spanish Speakers

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