alkali
Americannoun
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alkalis,
plural
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alkalies
plural
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Chemistry.
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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.
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any of various other more or less active bases, as calcium hydroxide.
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(not in technical use) an alkali metal.
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Obsolete. any of various other compounds, as the carbonates of sodium and potassium.
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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.
adjective
noun
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chem a soluble base or a solution of a base
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a soluble mineral salt that occurs in arid soils and some natural waters
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alkalis
plural
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Plants have difficulty growing in soil that is rich in alkalis.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of alkali
1300–50; Middle English alkaly < Middle French alcali < dialectal Arabic al-qalī, variant of Arabic qily saltwort ashes
Vocabulary lists containing alkali
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
These bacteria produce acid but are weak at generating alkali.
From Science Daily ● Jan. 9, 2026
They’re the pupae of alkali flies, a traditional food source of the Native Kootzaduka’a people.
From Los Angeles Times ● Aug. 8, 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
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
He drifted past saguaros and alkali flats, camped beneath escarpments of naked Precambrian stone.
From "Into the Wild" by Jon Krakauer
Pots, pans, vats, machines exposed to corrosives will be protected by a skin of aluminum, metal highly resistant to mos.t acids and alkalies.
From Time Magazine Archive
Humic, hū′mik, adj. denoting an acid formed by the action of alkalies on humus or mould.
From Chambers's Twentieth Century Dictionary (part 2 of 4: E-M) by Various
He deals with human character as a chemist with his acids and alkalies, and while he mixes his coloured fluids in a way that surprises the profane, knows perfectly well what he is about.
From Views and Reviews by James, Henry
It will be sufficient for our purpose just now to know that acids have a sour taste and that alkalies counteract acids.
From Household Administration Its Place in the Higher Education of Women by Various
The granules, which disappear on the addition of acids and alkalies, are apparently either added to the cell or result from a precipitation within the same.
From A System of Practical Medicine by American Authors, Vol. I Volume 1: Pathology and General Diseases by Various
In addition, the scientists substituted ammonium and tetramethyl ammonium, the former of which is mildly acidic, for the alkalis.
From Science Daily ● Feb. 12, 2024
Fermenting encompasses a range of processes through which microorganisms — yeasts, molds, bacteria — break down compounds in food to create alcohols, acids or alkalis, which in turn prevent the growth of harmful pathogens.
From Salon ● Dec. 6, 2023
Coal provided the power; the nascent chemical industry supplied the acids and alkalis essential to these enterprises.
From Nature ● Aug. 30, 2020
Alkalis were extracted from ashes, and soaps were prepared by combining these alkalis with fats.
From Textbooks ● Feb. 14, 2019
However polluted the former of these may be, still the vast advance which it made by the discovery of the principal acids, alkalis, and the more common of their salts, should be constantly recognized.
From De Re Metallica, Translated from the First Latin Edition of 1556 by Agricola, Georgius
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
