alkali

American  

[al-kuh-lahy] / ˈæl kəˌlaɪ /

noun

plural

alkalis, alkalies

1. Chemistry.

   1. any of various bases, the hydroxides of the alkali metals and of ammonium, that neutralize acids to form salts and turn red litmus paper blue.

   2. any of various other more or less active bases, as calcium hydroxide.

   3. (not in technical use) an alkali metal.

   4. Obsolete. any of various other compounds, as the carbonates of sodium and potassium.

2. Agriculture. a soluble mineral salt or a mixture of soluble salts, present in some soils, especially in arid regions, and detrimental to the growing of most crops.

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adjective

1. Chemistry. alkaline.

alkali British  

/ ˈælkəˌlaɪ /

noun

1. chem a soluble base or a solution of a base

2. a soluble mineral salt that occurs in arid soils and some natural waters

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alkali Scientific  

/ ăl′kə-lī′ /

plural

alkalis

1. A hydroxide of an alkali metal. The aqueous solution of alkalis is bitter, slippery, caustic, and characteristically basic in reactions.

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alkali Cultural  

1. A bitter, caustic mineral often found in large beds in the desert. Alkalis are bases; two common examples are lye and ammonia.

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Discover More

Plants have difficulty growing in soil that is rich in alkalis.

Etymology

Origin of alkali

1300–50; Middle English alkaly < Middle French alcali < dialectal Arabic al-qalī, variant of Arabic qily saltwort ashes

Example Sentences

And he has seen them descend on Mono Lake when the water is teeming with brine shrimp and the larvae and pupae of alkali flies.

From Los Angeles Times • Aug. 22, 2025

Another Los Angeles Times report on a roundup of immigrants begins by noting, “Human misery was compounded here today by a blistering desert sun and swirls of alkali dust.”

From Salon • Sep. 21, 2024

Because a vanadium peroxide molecule is negatively charged, it needed alkali cations for charge balance, Nyman said, and the researchers used potassium, rubidium and cesium alkali cations for this study.

From Science Daily • Feb. 12, 2024

The BBC's Mark Easton has been asking Commander Jon Savell about why it's taking time to find the alleged Clapham alkali attacker.

From BBC • Feb. 5, 2024

Experiments of the German Gerhard Schramm, first published in 1944, reported that TMV particles in mild alkali fell apart into free RNA and a large number of similar, if not identical, protein molecules.

From "Double Helix" by James D. Watson