[ thur-moh-set-ing ]
/ ˈθɜr moʊˌsɛt ɪŋ /


pertaining to a type of plastic, as the urea resins, that sets when heated and cannot be remolded.

Origin of thermosetting

First recorded in 1935–40; thermo- + setting Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for thermosetting

/ (ˌθɜːməʊˈsɛtɪŋ) /


(of a material, esp a synthetic plastic or resin) hardening permanently after one application of heat and pressure. Thermosetting plastics, such as phenol-formaldehyde, cannot be remouldedCompare thermoplastic
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

Science definitions for thermosetting

[ thûr′mō-sĕtĭng ]

Relating to a compound that softens when initially heated, but hardens permanently once it has cooled. Thermosetting materials are made of long-chain polymers that cross-link with each other after they have been heated, rendering the substance permanently hard. Compare thermoplastic.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.