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

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

Slowing degradation pathways The researchers also found that chlorine changes how the material degrades. —Aamir Khollam, Interesting Engineering, 30 Apr. 2026

In the 1930s, patients in Puerto Rico were subjected to experiments testing human tolerance to chlorine and mustard gas. —Uzma Rentia, STAT, 27 Apr. 2026

For white or color-fast sheets, add one-half cup of chlorine bleach to a standard washer or one-fourth cup to a high-efficiency washer in the bleach dispenser in addition to a high-quality laundry detergent. —Mary Marlowe Leverette, The Spruce, 25 Apr. 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