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 smaller firms are trying to break into the market with deals that are being viewed as a litmus test of investor appetite, CDO investors and managers said. Cezary Podkul, WSJ, "Hedge Funds Revive the Junk Bond CDO," 7 Nov. 2018 President Trump has repeatedly boasted about applying ideological litmus tests to compile his shortlist of 25 potential Supreme Court nominees. Caitlin Chen And Emily Cadei, sacbee, "'Terrifying': Advocates say abortion, gay rights threatened by Justice Anthony Kennedy's retirement," 27 June 2018 As the sharp debate over national immigration policy continues, support for abolishing the agency has become a litmus test for Democrats appealing to left-leaning activists and voters going into the midterm elections. Phillip M. Bailey, The Courier-Journal, "Abolish ICE movement pits practicality against passion for local Democrats," 10 July 2018 To be sure, the House is doing even less than the Senate to check Trump on trade (an issue that, until very recently, was a litmus test of conservatism). James Hohmann, Washington Post, "The Daily 202: Toothless trade resolution demonstrates Congress’s unwillingness to check Trump," 12 July 2018 So perhaps a litmus test for the next justice should simply be: Make him or her a middle child. Adam Sternbergh, The Cut, "The Extinction of the Middle Child," 11 July 2018 As for litmus tests, Democrats are more honest here. William Mcgurn, WSJ, "Abortion, Roe—and Trump," 2 July 2018 Even if the president never even asked them what the litmus test, that's the idea. Fox News, "Trump, Democrats gear up for Supreme Court showdown," 3 July 2018 The President just said the next Supreme Court nominee WILL come from his list of 25 judges that passed his overturning Roe v. Wade litmus test. Andrew Seidman,, "Justice Kennedy's retirement jolts midterm elections," 27 June 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

20 Nov 2018

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Time Traveler for litmus test

The first known use of litmus test was in 1913

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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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Spanish Central: Translation of litmus test

Nglish: Translation of litmus test for Spanish Speakers

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to move with a clumsy heavy tread

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