verb (used with object)

to make whiter or lighter in color, as by exposure to sunlight or a chemical agent; remove the color from.
Photography. to convert (the silver image of a negative or print) to a silver halide, either to remove the image or to change its tone.

verb (used without object)

to become whiter or lighter in color.


a bleaching agent.
degree of paleness achieved in bleaching.
an act of bleaching.

Origin of bleach

before 1050; Middle English blechen, Old English blǣcean, derivative of blāc pale; cognate with Old Norse bleikja, Old High German bleichēn
Related formsbleach·a·ble, adjectivebleach·a·bil·i·ty, nounhalf-bleached, adjectivenon·bleach, nouno·ver·bleach, verbre·bleach, verbsem·i·bleached, adjectiveun·bleached, adjectiveun·bleach·ing, adjective

Synonyms for bleach

1. See whiten. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for bleach

Contemporary Examples of bleach

Historical Examples of bleach

  • If ever time could bleach his own soul and conciliate hers, what, what was to become of Aphrodite?

    The Young Duke

    Benjamin Disraeli

  • She liked them to bleach on the line, it was almost as good as the grass.

    A Little Girl in Old Salem

    Amanda Minnie Douglas

  • The first of these is the bleach, or oxidizing mixture of bromide and ferricyanide.

  • "Lay them on the grass to bleach," said Daisy, with an air of experience.

    Little Men

    Louisa May Alcott

  • Kiss ye me till I be white, an' that will be an ill web to bleach.

    The Proverbs of Scotland

    Alexander Hislop

British Dictionary definitions for bleach



to make or become white or colourless, as by exposure to sunlight, by the action of chemical agents, etc


a bleaching agent
the degree of whiteness resulting from bleaching
the act of bleaching
Derived Formsbleachable, adjectivebleacher, noun

Word Origin for bleach

Old English blǣcan; related to Old Norse bleikja, Old High German bleih pale
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

Word Origin and History for bleach

Old English blæcan "bleach, whiten," from Proto-Germanic *blaikjan "to make white" (cf. Old Saxon blek, Old Norse bleikr, Dutch bleek, Old High German bleih, German bleich "pale;" Old Norse bleikja, Dutch bleken, German bleichen "to bleach"), from PIE root *bhel- (1) "to shine, flash, burn" (cf. Sanskrit bhrajate "shines;" Greek phlegein "to burn;" Latin flamma "flame," fulmen "lightning," fulgere "to shine, flash," flagrare "to burn;" Old Church Slavonic belu "white;" Lithuanian balnas "pale").

The same root probably produced black; perhaps because both black and white are colorless, or because both are associated with burning. Cf. Old English scimian, related to the source of shine (n.), meaning both "to shine" and "to dim, grow dusky, grow dark." Related: Bleached; bleaching.


"act of bleaching," 1887; "a bleaching agent," 1898, probably directly from bleach (v.). The Old English noun blæce meant "leprosy;" Late Old English also had blæco "paleness," and Middle English had blech "whitening or bleaching agent."

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for bleach



A chemical agent used to whiten or remove color from textiles, paper, food, and other substances and materials. Chlorine, sodium hypochlorite, and hydrogen peroxide are bleaches. Bleaches remove color by oxidation or reduction.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.