tri·​halo·​meth·​ane | \ (ˌ)trī-ˌha-lə-ˈme-ˌthān How to pronounce trihalomethane (audio) , British usually -ˈmē- \

Definition of trihalomethane

: any of various derivatives CHX3 of methane (such as chloroform) that have three halogen atoms per molecule and are formed especially during the chlorination of drinking water

Examples of trihalomethane in a Sentence

Recent Examples on the Web Multiple municipal tests over the years show water in Martin County exceeds the maximum contaminant level for trihalomethane and haloacetic acid, both byproducts of the water’s treatment and both carcinogenic. April Johnston,, "‘That's vinegar’: The Ohio River’s history of contamination and progress made," 26 Dec. 2019 But Veolia has said it was only hired by the city to assess bacteria and harmful chlorine compounds (trihalomethanes) in Flint’s water supply, not lead. Wired, "Utility Executives Kept Flint's Tainted Water a Secret," 13 Dec. 2019 In Dos Palos, where the water contains potentially harmful chemicals known as trihalomethanes, Joaquin Garcia has 5-gallon jugs of clean water delivered to his home. Dale Kasler, Phillip Reese And Ryan Sabalow, sacbee, "360,000 Californians have unsafe drinking water. Are you one of them?," 1 June 2018 And not only lead, but trihalomethane (TTHM) – a chemical byproduct of chlorine disinfectant. Richard Horan, The Christian Science Monitor, "'The Poisoned City' tells the horrific story of Flint's contaminated water," 10 July 2018 Until several months ago, customers received notices on the back of their water bills stating that their water had been tested and found to be above federal limits of trihalomethanes and haloacetic acids. Nadia Kounang, CNN, "The Kentucky county where the water smells like diesel," 30 Mar. 2018 The quality of the city’s drinking water has been a hot-button issue since routine testing in Nov. 2016 revealed elevated levels of trihalomethane, a disinfectant by-product. Brian Ballou,, "Castillo re-elected in Pines, Monroig out," 12 Mar. 2018 Unhealthy levels of trihalomethanes, or TTHMs, were reported by water utility companies in Wellington, Munroe Falls and Ravenna. James F. Mccarty,, "Contaminants taint some NE Ohio water, but EPA says safe to drink," 20 Oct. 2017 The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. Jennifer Larino,, "What is in your water? See test results for 19 New Orleans-area utilities," 3 Aug. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'trihalomethane.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of trihalomethane

1968, in the meaning defined above

Keep scrolling for more

Learn More about trihalomethane

Time Traveler for trihalomethane

Time Traveler

The first known use of trihalomethane was in 1968

See more words from the same year

Statistics for trihalomethane

Last Updated

7 Jan 2020

Cite this Entry

“Trihalomethane.” The Dictionary, Merriam-Webster Inc., Accessed 19 January 2020.

Keep scrolling for more

More Definitions for trihalomethane


tri·​halo·​meth·​ane | \ (ˌ)trī-ˌhā-lə-ˈmeth-ˌān, British usually -ˈmē-ˌthān \

Medical Definition of trihalomethane

: any of various derivatives CHX3 of methane (as chloroform) that have three halogen atoms per molecule and are formed especially during the chlorination of drinking water abbreviation THM

Comments on trihalomethane

What made you want to look up trihalomethane? Please tell us where you read or heard it (including the quote, if possible).


to insert between existing elements

Get Word of the Day daily email!

Test Your Vocabulary

The Eponym Quiz

  • rubens painting
  • Which is the best synonym of bowdlerize?
Spell It

Can you spell these 10 commonly misspelled words?

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!