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Synonyms

litmus test

American  

noun

  1. Chemistry. the use of litmus paper or solution to test the acidity or alkalinity of a solution.

  2. a crucial and revealing test in which there is one decisive factor.


litmus test British  

noun

  1. a test to establish the acidity or alkalinity of a mixture

  2. a critical indication of future success or failure

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of litmus test

First recorded in 1955–60; so called from chemical tests in which litmus or litmus paper is an indicator

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Playing in Friday's Chatrier day session against exciting Brazilian teenager Joao Fonseca, with temperatures set to reach 34C, will be a litmus test.

From BBC • May 28, 2026

They also provide a valuable litmus test for contemporary romance.

From Salon • Mar. 19, 2026

Still, many wondered if the Lakers’ litmus test would come from facing the defending champion Oklahoma City Thunder on Monday night.

From Los Angeles Times • Feb. 10, 2026

The watch became a litmus test of sorts: A guy was classified as a potential keeper if he didn’t mind the watch.

From Slate • Jan. 25, 2026

If unity is indeed the litmus test of human progress, neither history nor Heaven will readily forgive those who choose deliberately to raise their hands against it.

From One Common Faith by Baha'i International Community

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