Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

thoron

play
noun tho·ron \ˈthō(ə)r-ˌän, ˈthȯ(ə)r-\

Medical Definition of thoron

  1. :  a heavy radioactive isotope of radon of mass number 220 that is formed as a decay product of thorium, decays by emission of an alpha particle, and has a half-life of less than a minute




Seen and Heard

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

WORD OF THE DAY

immature or lacking adult sophistication

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image567572573

Which of these is a synonym of unctuous?

maudlin prompt oily angry
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

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

TAKE THE QUIZ