adjective
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Capable of neutralizing an acid. Bases are alkaline.
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Relating to an alkali compound.
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Having a pH greater than 7.
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Having a relatively low concentration of hydrogen ions.
Etymology
Origin of alkaline
Vocabulary lists containing alkaline
Chemistry - High School
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Chemistry - Middle School
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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.
Many of these organisms are capable of surviving under extreme conditions, including very high temperatures and strongly acidic or alkaline environments.
From Science Daily ● Aug. 12, 2026
PET responded well to the alkaline treatment, but polyethylene and polypropylene initially produced less hydrogen.
From Science Daily ● Jul. 31, 2026
Essentia, the supercharged ionized alkaline water, was for models and Kardashians.
From The Wall Street Journal ● Jul. 29, 2026
Despite its vivid blue appearance, the water at the quarry - dubbed the Blue Lagoon - is highly alkaline and potentially harmful, with a pH level comparable to bleach.
From BBC ● May 28, 2026
When the soil is too alkaline, which can be thought of as being too sweet, you need to add sulfur.
From "Counting by 7s" by Holly Goldberg Sloan
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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.