from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A hypothetical form of matter that is identical to physical matter except that its atoms are composed of antielectrons, antiprotons, and antineutrons.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Matter that is composed of the antiparticles of those that constitute normal matter.
- n. A form of matter that has a key property, such as charge, opposite to that of ordinary matter.
from the GNU version of the Collaborative International Dictionary of English
- n. Matter whch is composed of antiparticles such as antiprotons, positrons, and antineutrons.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. matter consisting of elementary particles that are the antiparticles of those making up normal substances
From anti- + matter. (Wiktionary)