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.

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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

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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

Sunday’s showdown with Kansas, and coach Bill Self, will be the ultimate litmus test of Pitino’s bold strategy.

From The Wall Street Journal

They also provide a valuable litmus test for contemporary romance.

From Salon

Next week brings one of the markets most crucial litmus tests of the artificial-intelligence trade, when chip maker Nvidia reports earnings on Wednesday.

From The Wall Street Journal

“We are removing litmus tests, not adding them.”

From The Wall Street Journal

Olympic qualification doesn’t involve a political litmus test—only citizenship, sportsmanship and skill.

From The Wall Street Journal