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 Investigating churches' compliance would consume an unsustainable amount of time and energy over something that shouldn't be a litmus test for fellowship, wrote Jeff Iorg, president of the SBC Executive Committee, in a Baptist Press commentary. CBS News, 6 June 2024 My mom is oftentimes my litmus test of whether or not something is working. Maureen Lee Lenker,, 23 May 2024 Elections also remain an important litmus test of public sentiment. Erika Solomon, New York Times, 21 May 2024 After dominating its first 10 games, Hammond faced a key litmus test on Jan. 10 against reigning Class 3A state champion and seven-time defending county champion Howard. Jacob Steinberg, Baltimore Sun, 20 Feb. 2024 See all Example Sentences for litmus test 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'litmus test.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1913, in the meaning defined above

Time Traveler
The first known use of litmus test was in 1913


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Cite this Entry

“Litmus test.” Dictionary, Merriam-Webster, Accessed 24 Jun. 2024.

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