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

The researchers measured the isotopic ratios of chlorine, oxygen, and carbon in these products. —Rupendra Brahambhatt, Interesting Engineering, 11 Jan. 2026

After you’re done cleaning up the kitchen or tackling tough stains around the house, a simple wash with oxygen bleach or a hint of chlorine bleach can make white towels look new again. —Caley Sturgill, Southern Living, 10 Jan. 2026

Water from the tap can contain minerals and chemicals, such as fluoride and chlorine, to which some plants are sensitive. —Samantha Johnson, Martha Stewart, 9 Jan. 2026

In video footage shared by the agency, the officers noted smelling chlorine. —Dan Raby, CBS News, 5 Jan. 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