Dictionary.com
Thesaurus.com

thoron

American  
[thawr-on, thohr-] / ˈθɔr ɒn, ˈθoʊr- /

noun

Chemistry.

  1. a radioactive isotope of radon, produced by the disintegration of thorium. Tn; 220; 86.

thoron British  
/ ˈθɔːrɒn /

noun

  1. a radioisotope of radon that is a decay product of thorium. Symbol: Tn or 220 Rn; atomic no: 86; half-life: 54.5s

"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

Etymology

Origin of thoron

First recorded in 1925–30; thor(ium) + -on 2

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.