Dictionary.com
Thesaurus.com
Synonyms

alkaline

American  
[al-kuh-lahyn, -lin] / ˈæl kəˌlaɪn, -lɪn /

adjective

Chemistry.

  1. of or like an alkali.

  2. containing an alkali.

  3. having the properties of an alkali.

  4. having a pH value greater than 7.

alkaline British  
/ ˈælkəˌlaɪn /

adjective

  1. having the properties of or containing an alkali

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
alkaline Scientific  
/ ăl′kə-lĭn,-līn′ /

  1. Capable of neutralizing an acid. Bases are alkaline.

  2. Relating to an alkali compound.

  3. Having a pH greater than 7.

  4. Having a relatively low concentration of hydrogen ions.

Etymology

Origin of alkaline

First recorded in 1670–80; alkal(i) + -ine 1

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.

“When the Emperor Was Divine” takes place in Utah, in “a city of tar-paper barracks behind a barbed-wire fence on a dusty alkaline plain.”

From The Wall Street Journal • Feb. 17, 2026

The best remedy for high pH, Wallace said, is to add gypsum to your soil and avoid things that can make the soil more alkaline, such as crushed concrete.

From Los Angeles Times • Apr. 24, 2025

The liquid is believed to be a type of home-made chilli spray with no strong acid or alkaline ingredients, police added.

From BBC • Feb. 18, 2025

Here, gut cells release the alkaline bicarbonate that neutralizes the stomach acid, and it is here that nutrients are absorbed.

From Science Daily • Dec. 2, 2024

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

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.