disinfectant

noun

dis·​in·​fec·​tant ˌdis-in-ˈfek-tənt 

plural disinfectants

: an agent used to disinfect something

especially : a chemical agent that is used especially on hard surfaces and in water (such as drinking water or wastewater) to destroy, inactivate, or significantly reduce the concentration of pathogens (such as bacteria, viruses, and fungi)

Note: Common chemical disinfectants include chlorine, calcium and sodium hypochlorite, iodophor, phenol, ethanol, and quaternary ammonium compounds. Disinfectants are often distinguished from sterilants by having reduced effectiveness against dormant bacterial endospores.

Examples of disinfectant in a Sentence

They use a strong disinfectant on the medical equipment.

Clean the area with disinfectant.

Recent Examples on the Web

This week in 1865, Joseph Lister became the first surgeon to perform an antiseptic operation with liberal use of carbolic acid (phenol) as a disinfectant. — Scott Lafee, San Diego Union-Tribune, 11 Aug. 2026

Using a disinfectant on a surface still covered with grease, grime or chicken slime will keep the chemical from reaching — and killing — the germs underneath unless the surface is first thoroughly cleaned. — Sandee Lamotte, CNN Money, 11 Aug. 2026

Hydrogen peroxide, commonly found in bathroom medicine cabinets, is a versatile disinfectant that also effectively sanitizes kitchen surfaces and removes grime. — Mary Marlowe Leverette, The Spruce, 2 Aug. 2026

Other toys can be carefully wiped down with disinfectant or white vinegar. — Brandee Gruener, Southern Living, 1 Aug. 2026

Word History

First Known Use

1837, in the meaning defined above

Rhymes for disinfectant

• expectant
• protectant

Kids Definition

disinfectant

noun

dis·​in·​fect·​ant

dis-ᵊn-ˈfek-tənt

: something (as a chemical) that is able to destroy harmful germs (as bacteria and fungi)

disinfectant adjective

Medical Definition

disinfectant

1 of 2 noun

dis·​in·​fec·​tant -ˈfek-tənt 

: an agent (as a chemical or ultraviolet light) that destroys, inactivates, or significantly reduces the concentration of pathogens (as bacteria, viruses, and fungi) especially on hard surfaces and in water (as drinking water or wastewater)

also : a preparation or formulation containing one or more disinfectants along with additional additives (as water and fragrance)

Note: Common chemical disinfectants include chlorine, calcium and sodium hypochlorite, iodophor, phenol, ethanol, and quaternary ammonium compounds. Disinfectants are often distinguished from sterilants by having reduced effectiveness against dormant bacterial endospores.

disinfectant

2 of 2 adjective

: serving or tending to disinfect : suitable for use in disinfecting