litmus test


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

But this is also a litmus test for Margot, who entered Friday having hit .258 with a .375 on-base percentage in his previous 59 games. San Diego Union-Tribune, "Padres notes: Machado’s slump assessment; Lamet’s prognostication; Hosmer’s helmet," 18 Aug. 2019 Some view chicken as a litmus test for a kitchen’s skill. Christina Tkacik,, "Inconsistent food and service make for a frustrating dining experience at Inner Harbor’s Blackwall Hitch," 15 Aug. 2019 And the issue of slavery reparations has emerged as a litmus test for the field. John Fritze, USA TODAY, "Democrats unified against Donald Trump's racist tweets but remain divided over race," 20 July 2019 Such requirements risk introducing a political litmus test into faculty hiring and reviews. Dan Walters, The Mercury News, "Walters: UC’s new political litmus test echoes McCarthy-era ‘oath’," 28 July 2019 There’s an early moment that doubles as a litmus test: driving a Trans Am (with an unfortunate but era-appropriate Confederate flag license plate emblem), Bandit eludes a police cruiser by zipping onto a side street. Keith Phipps, The Verge, "Before you see Once Upon a Time in Hollywood, watch Smokey and the Bandit," 26 July 2019 But the free-agent signing could emerge as a litmus test for general manager Eric DeCosta’s appraisal of the team this season. Jonas Shaffer,, "Ravens 2019 training camp preview: Cornerback," 22 July 2019 Therefore, the emergence of data showing that this is changing—and among Labour voters in particular—serves as a litmus test on the ascendance of regional dissatisfaction towards Westminster. Gareth Evans, Quartz, "The UK’s next prime minister must urgently answer five constitutional questions," 28 June 2019 Rivers' free agency should be a telling litmus test on both fronts. Ben Golliver,, "There’s more to this NBA free agency than superstars," 25 June 2019

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

28 Aug 2019

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Time Traveler for litmus test

The first known use of litmus test was in 1913

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More Definitions for litmus test

litmus test


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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one from the Upper Peninsula of Michigan

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