lye

American  

[lahy] / laɪ /

noun

Chemistry.

1. a highly concentrated, aqueous solution of potassium hydroxide or sodium hydroxide.

2. any solution resulting from leaching, percolation, or the like.

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lye British  

/ laɪ /

noun

1. any solution obtained by leaching, such as the caustic solution obtained by leaching wood ash

2. a concentrated solution of sodium hydroxide or potassium hydroxide

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lye Scientific  

/ lī /

1. A strong alkaline solution or solid of potassium hydroxide or sodium hydroxide, made by allowing water to wash through wood ashes. It is used to make soap and drain and oven cleaners. Chemical formula: KOH or NaOH.

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Etymology

Origin of lye

First recorded before 900; Middle English lie, ley, Old English lēag; cognate with Dutch loog, German Lauge “lye,” Old Norse laug “warm bath”; see lave ¹

Explanation

Lye is an alkaline solution that's used for cleaning. If you were a maid about 200 years ago, you probably cleaned the chamber pots with lye. Lye is an old cleaning product and an old word too. It comes from the Old English léag, which is related to the root for "wash" in our word lather. Lye is still used to make soap, but you probably won't come across the word except in old novels. If you become a historical re-enactor, say goodbye to body wash and hello to lye.

Example Sentences

The operator watched as the intruder clicked into various software programs before landing on a function that controls the amount of sodium hydroxide, or lye, in the plant’s water system.

From Los Angeles Times • May 8, 2023

Traditional pretzels are dipped in a lye solution to give them that quintessential pretzel tang and gorgeous color — but this fun home-baking project relies instead upon baking soda.

From Seattle Times • Apr. 23, 2023

To make the humanmade version, the team first softened thin strips of oak by boiling them with lye and sodium sulfite.

From Science Magazine • Feb. 15, 2023

My friend Erin Clarkson of Cloudy Kitchen finally produced a beautiful pretzel without lye, and it inspired me to try, too.

From Salon • Oct. 10, 2022

Charles had moved into a shed where his nostrils would not be assailed by the immaculate but painful smells of lye and soda and ammonia and yellow soap.

From "East of Eden" by John Steinbeck