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

Most modern manufacturers bleach white office paper with chlorine dioxide, which creates fewer byproducts than chlorine bleach and breaks down quickly.1 Some use entirely chlorine-free methods for bleaching. —Brandee Gruener, Southern Living, 30 Apr. 2025

The reason: Unfiltered tap water often contains at least tiny amounts of chlorine, which can harm the yeast and bacteria that make your starter active. —Emily Williams, Better Homes & Gardens, 28 Mar. 2025

Swimming in Pools Swimming pools are full of chlorine and other chemicals, which is hard on hair and can dry it out. —Patty Weasler, Rn, Verywell Health, 28 Mar. 2025

One monitor, about 11 miles south of the Eaton fire in the foothills of the San Gabriel Mountains, detected 40 times the normal amount of chlorine in the air and 110 times the typical amount of lead in the days following the fires. —Katharine Gammon, Scientific American, 27 Mar. 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