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 That issue may provide an early sign of whether cooperation indeed remains possible, and the litmus test won’t involve meetings, diplomatic overtures, sanctions, or rhetorical exchanges. Ned Temko, The Christian Science Monitor, 1 Apr. 2021 Trump, who is planning a Phoenix rally July 24, is closely watching that review and is using it as a litmus test to assess the GOP Senate candidates’ loyalty to him. Yvonne Wingett Sanchez, The Arizona Republic, 13 July 2021 The Covid-19 pandemic has been a litmus test for leadership across the world. Devapriya Khanna, Forbes, 5 July 2021 In that sense, the Fire FC match will be viewed externally as a kind of litmus test and gauge of Cincinnati's ability to evade a third-consecutive last-place finish, albeit with more than two-thirds of the schedule still to be played. Pat Brennan, The Enquirer, 21 June 2021 This article is the turn of VMware to pass the litmus test to be a trustworthy multi-cloud provider. Patrick Moorhead, Forbes, 8 June 2021 Ducey, who is at the forefront of GOP efforts to grow the number of governors' mansions the party controls, already failed that litmus test. Gabby Orr, CNN, 27 May 2021 Employee surveys can provide a good litmus test, and employee resource groups (ERGs) can provide a natural place for check-ins. Alexandra Ossola, Quartz, 4 Apr. 2021 TC Energy has ended its 16-year quest to build the Keystone XL oil pipeline, a controversial cross-border project that became a litmus test for climate activism and was blocked by President Joe Biden. Time, 10 June 2021

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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Time Traveler for litmus test

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The first known use of litmus test was in 1913

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Last Updated

29 Jul 2021

Cite this Entry

“Litmus test.” Dictionary, Merriam-Webster, Accessed 5 Aug. 2021.

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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

More from Merriam-Webster on litmus test

Thesaurus: All synonyms and antonyms for litmus test

Nglish: Translation of litmus test for Spanish Speakers


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