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

National Park Service crews dumped hydrogen peroxide into the water last week and then pieces of the new flooring started breaking loose as crews began vacuuming the pool floor.

From The Wall Street Journal ● Jun. 22, 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

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

In an effort combat the algae in the Reflecting Pool, employees of the National Park Service were seen pouring in gallons of hydrogen peroxide, a chemical commonly used in pool maintenance.

From Los Angeles Times ● Jun. 20, 2026

At bedtime we’d shake a little baking soda into the palm of one hand, mix in a dash of hydrogen peroxide, then use our fingers to clean our teeth with the fizzing paste.

From "The Glass Castle" by Jeannette Walls