hydrogen peroxide

noun

: an unstable compound H2O2 used especially as an oxidizing and bleaching agent, an antiseptic, and a propellant

Examples of hydrogen peroxide in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The hydrogen peroxide treatment then attacks the remaining dye-cotton linkages and removes residual color. — Alexandra Harrell, Footwear News, 26 Aug. 2026 McGowen recommends mixing it with hydrogen peroxide to form a paste, then leaving it on for 20 to 30 minutes. — Lauren Dana Ellman, Travel + Leisure, 19 Aug. 2026 Sometimes, unexpected household items can be useful in the garden, like hydrogen peroxide. — Mallory Carra, The Spruce, 19 Aug. 2026 Oxygen Bleach, Explained Meanwhile, in place of chlorine, oxygen bleach relies on sodium carbonate and hydrogen peroxide for its effectiveness. — Caroline Lubinsky, Martha Stewart, 16 Aug. 2026 See All Example Sentences for hydrogen peroxide

Word History

First Known Use

1872, in the meaning defined above

Time Traveler
The first known use of hydrogen peroxide was in 1872

Rhymes for hydrogen peroxide

See All Rhymes for hydrogen peroxide

Browse Nearby Words

hydrogen oxide
hydrogen peroxide
hydrogen selenide
See all Nearby Words

Cite this Entry

“Hydrogen peroxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hydrogen%20peroxide. Accessed 2 Sep. 2026.

Copy Citation

Kids Definition

hydrogen peroxide

noun
: an unstable liquid compound containing hydrogen and oxygen and used especially for bleaching and as an antiseptic

Medical Definition

hydrogen peroxide

noun
: an unstable compound H2O2 used especially as an oxidizing and bleaching agent and as an antiseptic

More from Merriam-Webster on hydrogen peroxide

Britannica.com: Encyclopedia article about hydrogen peroxide

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of dissonant

See Definitions and Examples »

Popular in Grammar & Usage

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?

Why does English have so many silent letters?

7 Pairs of Commonly Confused Words
See More

Popular in Wordplay

See More

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

Even More Words That Sound Like Insults But Aren't

Even More Bird Names that Sound Like Insults (and Sometimes Are)

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
skateboard-dog-hat
Wordmaxxing Slang Quiz Give your vocabulary a glow up by getting sendy w...
See All