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

Pre-filters remove sediment and chlorine, the RO membrane performs primary contaminant reduction, and post-filters improve taste. —Malana Vantyler, USA Today, 6 May 2026

This flattering swimsuit features adjustable straps and is made from a chlorine-resistant material that provides UPF 50+ sun protection. —Caroline Hughes, Travel + Leisure, 5 May 2026

Spray mouse nests and droppings with a 10 percent solution of chlorine bleach or similar disinfectant. —Tom Gavin, EverydayHealth.com, 5 May 2026

Mussels can be treated using chlorine, copper and Zequanox, made from a naturally occurring bacterium that causes the mussels to stop feeding and die, Marrone said. —Julia Jacobo, ABC News, 1 May 2026

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