A hypothetical form of matter that is identical to physical matter except that its atoms are composed of antielectrons, antiprotons, and antineutrons. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "antimatter" in a sentence
"McGregor joins the Brown franchise as Camerlegno Carlo Ventresca, a papal aide that assists Langdon and Vetra in their search for the canister in which the antimatter is contained."
"Kobayashi and Maskawa hypothesized the existence of a third family of quarks, which are some of the building blocks from which all matter and antimatter is formed."
"At the end of the story, the pope -- a religious fanatic -- dies, as does another character who proves to be a science fanatic, equally dangerous and more vicious besides, leaving open the question of whether harnessing antimatter is a good idea or not."