hydrogen peroxide

American  

noun

1. a colorless, unstable, oily liquid, H 2 O 2 , an aqueous solution of which is used chiefly as an antiseptic and a bleaching agent.

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hydrogen peroxide British  

noun

1. a colourless oily unstable liquid, usually used in aqueous solution. It is a strong oxidizing agent used as a bleach for textiles, wood pulp, hair, etc, and as an oxidizer in rocket fuels. Formula: H 2 O 2

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hydrogen peroxide Scientific  

1. A colorless, dense liquid, that is often used as a bleach or is diluted with water for use as an antiseptic. Chemical formula: H ₂ O ₂ .

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Etymology

Origin of hydrogen peroxide

First recorded in 1870–75

Example Sentences

And the unique printing process of Bonnie Ralston, shown by Arts Gowanus, uses found metal objects, salt, vinegar and hydrogen peroxide to create ghostly industrial prints out of corrosion.

From The Wall Street Journal • Apr. 10, 2026

Experiments confirmed that hydrogen peroxide alone could cause isolated crystals to spin, even outside the parasite.

From Science Daily • Mar. 19, 2026

"We think that the breakdown of hydrogen peroxide likely makes an important contribution to reducing cellular stress," Sigala says.

From Science Daily • Mar. 19, 2026

However, products sold to undercover BBC reporters were sent to a laboratory for tests where results showed they contained hydrogen peroxide levels of up to 53%.

From BBC • Oct. 28, 2025

Until well into the second half of the century, the formula H2O2 might mean water to one chemist but hydrogen peroxide to another.

From "A Short History of Nearly Everything" by Bill Bryson