bio·​cide ˈbī-ə-ˌsīd How to pronounce biocide (audio)
: a substance (such as an algicide or fungicide) that destroys or inhibits the growth or activity of living organisms
Sodium azide is an explosive, broad-spectrum biocide with toxicity comparable to sodium cyanide's.Science News

Example Sentences

Recent Examples on the Web Yet, without a functional waste management system, plastic and other non- biodegradable trash accumulates on roadsides, mountain creeks and beaches, often seeping biocides that further degrade those ecosystems. Vogue, 17 Feb. 2023 No one is planning to inflict massive biocide like Thanos in the Marvel Avengers films. Matthew Cobb, Scientific American, 13 Jan. 2023 There’s growing concern that overuse of triclosan, the biocide in hand soap, leads to the emergence of drug-resistant bacteria, disrupts hormones in the body and may contribute to certain types of cancer. Carl Engelking, Discover Magazine, 2 Sep. 2016 For brick pavers that get a greenish or blackish hue from moss and lichen, damp shady environments, or water run-off, the BIA recommends bleach and water (mixed with a one-to-one ratio) or commercially available biocide treatments. Kristina Mcguirk, Better Homes & Gardens, 16 June 2022 Another target is to cut pollution from biocides, plastic wastes, and excess nutrients by at least 50%. Jessie Yeung, CNN, 14 Jan. 2020 Waterford masks contain a biocide that protects medical workers and other wearers from infectious diseases better than existing masks, which were designed more to safeguard patients than wearers, the company says. Joseph A. Mann Jr, miamiherald, 9 Mar. 2018 A class of biocides known as quaternary ammonium compounds, or quats, is one chemical treatment that temporarily diminishes biofilms and their visible effects. National Geographic, 21 Sep. 2016 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'biocide.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1947, in the meaning defined above

Time Traveler
The first known use of biocide was in 1947

Dictionary Entries Near biocide

Cite this Entry

“Biocide.” Dictionary, Merriam-Webster, Accessed 8 Jun. 2023.

Medical Definition


bio·​cide ˈbī-ə-ˌsīd How to pronounce biocide (audio)
: a substance (as glutaraldehyde) that is destructive to many different organisms
biocidal adjective
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