litmus

[ lit-muhs ]

noun

1. a blue coloring matter obtained from certain lichens, especially Roccella tinctoria. In alkaline solution litmus turns blue, in acid solution, red: widely used as a chemical indicator.

litmus

/ ˈlɪtməs /

noun

1. a soluble powder obtained from certain lichens. It turns red under acid conditions and blue under basic conditions and is used as an indicator

litmus

/ lĭt′məs /

1. A colored powder, obtained from certain lichens, that changes to red in an acid solution and to blue in an alkaline solution. Litmus is a mixture of various closely related heterocyclic organic compounds.
2. ◆ Litmus is typically added to paper to make litmus paper , which can be used to determine whether a solution is basic or acidic by dipping a strip of the paper into the solution and seeing how the paper changes color.

litmus

1. In chemistry , a kind of paper used to tell whether a solution is an acid or a base . Acids turn blue litmus paper red; bases turn red litmus paper blue. Other testing paper or sophisticated instruments can be used to measure the pH of a solution more precisely.

Notes

The term litmus is often used to refer to a general and simple test: “Your vote on this issue is a litmus test of your political philosophy .”

Word History and Origins

Origin of litmus¹

1495–1505; earlier lytmos < Old Norse litmosi dye-moss, equivalent to lit- color, dye + mosi moss

Word History and Origins

Origin of litmus¹

C16: perhaps from Scandinavian; compare Old Norse litmosi, from litr dye + mosi moss

Example Sentences

While campaigning against Clinton, Trump had positioned his victory as a litmus test for democracy.

From Los Angeles Times

Support of abortion bans as a litmus test for GOP politicians took some time to reach its full flowering.

From Los Angeles Times

This isn’t to say playing me bowling well is a litmus test for being a good batter, far from it.

From BBC

Where Schiff and Garvey stand on the Republican, who is again running for president, has repeatedly been used — including by the two campaigns — as a litmus test for their politics.

From Los Angeles Times

Still, the poll results will be seen as a litmus test ahead of Germany's federal elections in 2025.

From BBC