litmus test

noun

: a test in which a single factor (such as an attitude, event, or fact) is decisive

Did you know?

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 something 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

Yet in the 12 games since his return, despite initial rustiness, Flagg has enhanced his diverse talents, a clear indication Kidd’s early-season decision to play him at point guard was a beneficial litmus test. —Brad Townsend, Dallas Morning News, 28 Mar. 2026

The opening series is a litmus test. —Jaylon Thompson, Kansas City Star, 26 Mar. 2026

Hating vaccines became a MAGA litmus test. —Literary Hub, 23 Mar. 2026

Paraclete and Saint Joseph’s first matchup is Thursday, and that game will be an early litmus test for both squads. —Matt Wagner, Daily News, 18 Mar. 2026

Word History

First Known Use

1913, in the meaning defined above

Rhymes for litmus test

• acquiesced
• coalesced
• dispossessed
• manifest
• overdressed
• overstressed
• prepossessed
• reassessed
• reinvest
• repossessed
• unaddressed
• uncompressed

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