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

"Either you're in for war fighting and that's it, that's the only litmus test we care about," Hegseth told the Shawn Ryan Show, in an episode released last week.

From BBC

“I always put the old birth control litmus test to it,” Lowe said.

From Los Angeles Times

“Under Trump, higher education in the US will face a difficult future, featuring an aggressive and intrusive federal government, erosion in funding with no alternatives, a cavalcade of political litmus tests and a decline in the US’s science and technology capability,” wrote John Aubrey Douglass, a senior research fellow and research professor of public policy and higher education at the UC Berkeley Center for Studies in Higher Education.

From Los Angeles Times

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