What does chlorinate mean?
To chlorinate is to treat a substance — most commonly water — with chlorine in order to disinfect it and destroy harmful microorganisms such as bacteria and viruses. The practice is one of the great public-health achievements of the modern era: since municipalities began chlorinating drinking water in the early twentieth century, waterborne diseases like cholera and typhoid have fallen dramatically across much of the world. Beyond water treatment, the word has a broader chemical sense, referring to the introduction of chlorine atoms into compounds during industrial processes. In everyday speech it appears most often in connection with swimming pools, where 'chlorinated' signals clean, treated water. The word derives from 'chlorine,' itself named from the Greek 'chloros,' meaning pale green, after the gas's distinctive color. Related forms include 'chlorination' (the process) and 'dechlorinate' (its reverse).
verbTo treat water or another substance with chlorine, typically to disinfect it and kill harmful bacteria.
- To treat water or other substances with chlorine in order to disinfect them.
- (Chemistry, broader use) To combine or impregnate a compound with chlorine.
"The city chlorinates its drinking water to keep it safe from contamination."
"Municipal treatment plants chlorinate the water supply before it reaches people's homes."
"Early twentieth-century chemists learned to chlorinate organic compounds to produce new industrial materials."
That unmistakable 'pool smell' isn't actually chlorine — it's chlorine reacting with sweat and urine, which is why properly chlorinated pools barely smell at all.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chlorinate
Chlorinate is formed from 'chlorine,' the name given by Sir Humphry Davy in 1810 to the newly isolated greenish-yellow gas, combined with the verb-forming suffix '-ate.' Chlorine itself derives from the Greek 'chloros,' meaning pale green or yellowish-green, a reference to the gas's color. The verb arose in nineteenth-century scientific usage as chemists developed methods for introducing chlorine into substances, and it entered widespread everyday language as municipal water chlorination became routine in the early twentieth century. It shares its Greek root with related terms such as chlorophyll and chloroform.
Related word forms
How chlorinate is actually used
Chlorinate is primarily a technical and practical term used in contexts of water treatment, public health, and chemistry. It is neutral in tone but carries broadly positive connotations of hygiene and safety when applied to drinking water or pools. The verb is standard in both British and American English, with no meaningful regional variation.
Easily confused with chlorinate
Chlorine is the chemical element itself, while chlorinate is the verb describing the act of treating something with chlorine.