Meaning of antimatter

an•ti•mat•ter

Pronunciation: (an'tē-mat"ur, an'tī-), [key]
— n. Physics.
  1. matter composed only of antiparticles, esp. antiprotons, antineutrons, and positrons.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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