chlorine

noun

chlo·​rine ˈklȯr-ˌēn 

-ən

: a halogen element that is isolated as a heavy greenish-yellow diatomic gas of pungent odor and is used especially as a bleach, oxidizing agent, and disinfectant in water purification see Chemical Elements Table

Examples of chlorine in a Sentence

Recent Examples on the Web

Blondes might experience a greenish tint from chlorine while brunettes and redheads can struggle with brassiness from sun, salt water, and chlorine exposure. —Holly Carter, People.com, 9 June 2025

Two officials briefed on the matter said the chemical weapons appeared to use chlorine gas, which can cause lasting damage to human tissue, the New York Times reported at the time. —Reuters, CNN Money, 23 May 2025

The cancer-causing mineral, which is not generally considered critical to national security or the U.S. economy, is still used to make chlorine, but the Biden administration’s Environmental Protection Agency banned imports of the material last year. —Robert Faturechi, ProPublica, 22 Apr. 2025

There are three hot-water relaxation pools, and the water from the pools and showers is all filtered in-house, without chemicals or chlorine. —Chiara Barzini, Vogue, 3 June 2025

Word History

First Known Use

1810, in the meaning defined above

Phrases Containing chlorine

• chlorine dioxide
• chlorine monoxide

Rhymes for chlorine

• organochlorine

Kids Definition

chlorine

noun

chlo·​rine ˈklō(ə)r-ˌēn 

ˈklȯ(ə)r-,

-ən

: a nonmetallic element that is found alone as a heavy greenish yellow irritating gas having two atoms per molecule and a strong odor and that is used especially as a bleach, oxidizing agent, and disinfectant in water purification see element

Medical Definition

chlorine

noun

chlo·​rine ˈklō(ə)r-ˌēn, ˈklȯ(ə)r-, -ən 

: a halogen element that is isolated as a heavy greenish yellow gas of pungent odor and is used especially as a bleach, oxidizing agent, and disinfectant in water purification

—symbol Cl see Chemical Elements Table