1. a plastic of this type.

Origin of thermoplastic

First recorded in 1880–85; thermo- + plastic
Related formsther·mo·plas·tic·i·ty [thur-moh-pla-stis-i-tee] /ˌθɜr moʊ plæˈstɪs ɪ ti/, nounnon·ther·mo·plas·tic, adjective, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for thermoplastic


  1. (of a material, esp a synthetic plastic or resin) becoming soft when heated and rehardening on cooling without appreciable change of propertiesCompare thermosetting
  1. a synthetic plastic or resin, such as polystyrene, with these properties
Derived Formsthermoplasticity (ˌθɜːməʊplæˈstɪsɪtɪ), noun
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

Word Origin and History for thermoplastic

1883, see thermo- + plastic. As a noun from 1929.

Online Etymology Dictionary, © 2010 Douglas Harper

thermoplastic in Science


  1. Of or relating to a compound that can be repeatedly made soft and hard through heating and cooling. Polyethylene and polystyrene are thermoplastic resins. Compare thermosetting.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.