matter composed only of antiparticles, especially antiprotons, antineutrons, and positrons.
Origin of antimatter
First recorded in 1950–55; anti-
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for antimatter
Contemporary Examples of antimatter
Historical Examples of antimatter
On the average, one atom out of every ten million in the universe was an atom of antimatter.
The distribution was unequal of course; antimatter could not exist in contact with ordinary matter.
British Dictionary definitions for antimatter
a form of matter composed of antiparticles, such as antihydrogen, consisting of antiprotons and positrons
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for antimatter
Online Etymology Dictionary, © 2010 Douglas Harper
A form of matter that consists of antiparticles.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.