per·​ox·​ide | \pə-ˈräk-ˌsīd \

Definition of peroxide 

(Entry 1 of 3)

: a compound (such as hydrogen peroxide) in which oxygen is visualized as joined to oxygen


peroxided; peroxiding

Definition of peroxide (Entry 2 of 3)

transitive verb

: to treat with a peroxide especially : to bleach (hair) with hydrogen peroxide



Definition of peroxide (Entry 3 of 3)

: having or being bleached hair a peroxide blonde

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Other Words from peroxide


peroxidic \pə-​ˌräk-​ˈsi-​dik \ adjective

Examples of peroxide in a Sentence

Recent Examples on the Web: Noun

For it, Gaga still rocks her peroxide-blonde hair and dark, feathered brows. Leah Prinzivalli, Allure, "Lady Gaga's Minimalist Look for Vogue's October Cover Was Done With Just $50 of Drugstore Makeup," 10 Sep. 2018 Without those generators, the organic peroxides made at the plant grew unstable and ultimately ignited, spreading noxious smoke for miles. Erin Ailworth, WSJ, "Texas Grand Jury Indicts Chemical Company for Harvey Explosion," 3 Aug. 2018 When a harvest is finished, replace the rock wool and clean the system's reservoir, pump, and tubing with a 3 percent hydrogen-peroxide solution. Daniel Kluko, Popular Mechanics, "How to Grow Hydroponic Plants at Home," 13 Feb. 2017 The California native took on a British accent, and his brown hair was crisped and brightened with peroxide. Andrew Dansby, Houston Chronicle, "‘Buffy’ vampire James Marsters comes out in the daylight for Comicpalooza," 23 May 2018 For those who wear their contact lenses for a couple of weeks or a month, Haberman says that peroxide solutions, like ClearCare, will help reduce the risk of infection. Katie Heaney, The Cut, "Are My Contacts Going to Make Me Go Blind?," 11 July 2018 The crying woman appears to be in an abusive relationship, and the scrawny singer, his hair in peroxide-blond spikes, seems to narrate her emotions. Spencer Kornhaber, The Atlantic, "What Linkin Park Gave to Pop Music," 25 June 2018 While peroxide is still the gold-standard ingredient to make teeth sparkle, those concerned about its harshness have a number of alternative ingredients to help keep their smile bright. Marci Robin, Allure, "The 10 Best Whitening Toothpastes, According to Dentists," 7 Mar. 2018 Instead, Debbie renews her ties with nightclub owner Lou (Blanchett, rocking peroxide-blond bangs and aviator shades), who used to be her confidante and partner, in possibly more than one sense. Justin Chang,, "Sandra Bullock and Cate Blanchett pull off an enjoyable, low-fizz heist in 'Ocean's 8'," 6 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'peroxide.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of peroxide


1804, in the meaning defined above


1899, in the meaning defined above


1899, in the meaning defined above

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Statistics for peroxide

Last Updated

6 Dec 2018

Look-up Popularity

Time Traveler for peroxide

The first known use of peroxide was in 1804

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More Definitions for peroxide



English Language Learners Definition of peroxide

: a chemical that is used chiefly to kill bacteria or to make hair lighter in color


per·​ox·​ide | \pə-ˈräk-ˌsīd \

Kids Definition of peroxide


per·​ox·​ide | \pə-ˈräk-ˌsīd \

Medical Definition of peroxide 

: a compound (as hydrogen peroxide) in which oxygen is visualized as joined to oxygen

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More from Merriam-Webster on peroxide

Spanish Central: Translation of peroxide

Nglish: Translation of peroxide for Spanish Speakers

Britannica English: Translation of peroxide for Arabic Speakers Encyclopedia article about peroxide

Comments on peroxide

What made you want to look up peroxide? Please tell us where you read or heard it (including the quote, if possible).


the figure or shape of a crescent moon

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