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 two compounds, sodium hypochlorite and hydrochloric acid, can create deadly chlorine gas if mixed. —Caitlin McGlade, Charlotte Observer, 10 Apr. 2026

So far, the city has completed several major components of the Springbrook improvement project, including adding in an ultraviolet disinfection system that replaced the facility’s old chlorine disinfection system and adding new pumps at the influent pump station. —Carolyn Stein, Chicago Tribune, 8 Apr. 2026

This isn’t caused by too little water or too much sun, but rather by the chemicals in tap water, such as fluoride and chlorine. —Karen Brewer Grossman, Southern Living, 5 Apr. 2026

In 1915, chlorine gas became the first lethal chemical weapon used on the battlefield in World War I, and the German dye industry was the main supplier. —Literary Hub, 2 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