trihalomethane noun a type of chemical compound in which three of the hydrogen atoms in a methane molecule have been replaced by halogen atoms, esp by chlorine in drinking water. Trihalomethanes are thought to be carcinogenic
Collins English Dictionary – Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 trihalomethane in Science trihalomethane [trī′hăl-ə-mĕth′ān′] Any of various organic compounds containing three halogen atoms substituted for three of the hydrogen atoms in a methane molecule. It can occur in chlorinated water as a result of reaction between organic materials in the water and chlorine added as a disinfectant. Chloroform is a trihalomethane. The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.