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 given the events of the past two weeks, the effect of not having litmus tests is suddenly very clear. Lily Herman,, "Actually, Abortion Litmus Tests Are A Good Thing," 8 June 2019 What happens next will be a litmus test for Canada’s process of national reconciliation. Annabelle Timsit, Quartz, "Canada begins reconciliation process after inquiry into missing or murdered indigenous women ends," 7 June 2019 One reason Trump has become a conservative litmus test is that there’s a policy vacuum on the right, and Trump’s personality is filling the void. Jonah Goldberg, National Review, "USS John S. McCain Episode Speaks Volumes about Trumpism," 5 June 2019 This will season will be a litmus test for the defending champions, who will be out to prove their success is sustainable without Ty Jerome, Kyle Guy and De’Andre Hunter. Jeremy Woo,, "Top 25 Reset: How Draft Decisions Changed Our 2019-20 Preseason Rankings," 5 June 2019 The litmus test for the sincerity of Mr. Zuckerman’s convictions... WSJ, "Shireman and Allies Want To Kill For-Profit Schools," 15 Mar. 2019 Stefanik is decidedly against having a political litmus test. Rebecca Gale, Marie Claire, "Elise Stefanik Is Going to Bring Women Back to the GOP," 25 Mar. 2019 Alternatively, the committee can keep putting purity above pragmatism, and take needlessly divisive stands in support of candidates who meet its litmus tests. Eric Levitz, Daily Intelligencer, "‘Rigging’ Primaries Is Fine. Backing Bad Candidates Isn’t.," 27 Apr. 2018 Being liberal is the litmus test of political decency. Tunku Varadarajan, WSJ, "If America Is Divided, So Is Europe," 6 July 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

19 Jun 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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