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

That includes getting ammonia and residual chlorine runoff — which flows into Indian Creek, a tributary of the Boise River — under DEQ’s limits. —Rose Evans, Idaho Statesman, 14 Aug. 2025

Rose noted that the chlorine from the pool water caused the suit to shrink. —Edward Segarra, USA Today, 12 Aug. 2025

The chlorine is rinsed off before packaging and is considered safe by food safety standards. —Katie Rosenhouse, Southern Living, 10 Aug. 2025

The season's triple threat of UV rays, chlorine, and saltwater creates a perfect storm of damage that goes far deeper than surface-level dryness. —Pooja Shah, Forbes.com, 10 Aug. 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