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

See Examples For:

hydrogen peroxide

In laboratory studies, high-dose vitamin C helps generate hydrogen peroxide, a reactive substance that can damage cells.

From Science Daily ● Aug. 7, 2026

Officials have been using chemicals, including reportedly hydrogen peroxide, to clean a green algae bloom which has taken hold in the pool since it was re-filled following a paint job earlier this month.

From BBC ● Jun. 22, 2026

National Park Service workers this week have been trying to clean the algae blooms off the bottom of the 2,000-foot-long pool by pouring hydrogen peroxide into the water and vacuuming the floor.

From The Wall Street Journal ● Jun. 21, 2026

As workers scrambled to pump out murky water and dumped hydrogen peroxide into the pool, Trump took no responsibility for what many observers chalked up to shoddy workmanship.

From Barron's ● Jun. 21, 2026

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