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

antimatter

play
noun an·ti·mat·ter \ˈan-tē-ˌma-tər, ˈan-ˌtī-\

Definition of antimatter

  1. :  matter composed of antiparticles



1950

First Known Use of antimatter

1950


Learn More about antimatter


Seen and Heard

What made you want to look up antimatter? 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?

oily angry maudlin prompt
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