Definition of litmus
1 : a coloring matter from lichens that turns red in acid solutions and blue in alkaline solutions and is used as an acid-base indicator
2 : the critical factor in a litmus test; also : litmus test
Recent Examples of litmus from the Web
Daniels acknowledged, however, that the Rangers’ 10-game road trip against teams in wild card contention, including the Royals, Orioles and Rays, poses a good litmus test right out of the gate for the club’s second-half prospects.
Such a belief cannot be, and frankly has never been, the litmus test for policy in the Republican Party.
The past week has brought a career-defining litmus test for secretaries of state in capitals across the country.
In more seriousness, the home opener should give the Steelers an early litmus test against what was one of the league's best defenses last year.
The car isn’t just a make-or-break vehicle for Tesla but a litmus test for whether the electric-vehicle market can go mainstream at more than niche sales levels.
The litmus test that separates the natives from the outsiders or tourists is the way the street names are pronounced.
The Heat can get appreciably closer to that by adding Gordon Hayward or Blake Griffin, this club's litmus test for summer success.
The KKW by Kylie Cosmetics crème lipstick set was a litmus test.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'litmus'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Origin and Etymology of litmus
Middle English litmose, of Scandinavian origin; akin to Old Norse litmosi herbs used in dyeing, from litr color (akin to Old English wlite brightness, appearance) + mosi moss; akin to Old English mōs moss
First Known Use: 14th centurySee Words from the same year
Medical Definition of litmus
: a coloring matter from lichens that turns red in acid solutions and blue in alkaline solutions and is used as an acid-base indicator
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