[ an-tee-at-uhm, an-tahy- ]
/ ˈæn tiˌæt əm, ˈæn taɪ- /
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noun Physics.
an atom of antimatter.
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“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

Origin of antiatom

First recorded in 1965–70; anti- + atom
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use antiatom in a sentence

British Dictionary definitions for antiatom


an atom composed of antiparticles, in which the nucleus contains antiprotons with orbiting positrons
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for antiatom

[ ăntē-ăt′əm, ăn′tī- ]

An atom composed of antiparticles. An antiatom consists of positrons, antiprotons, and antineutrons. It has the same mass and spin as an ordinary atom, and the same amount of charge and magnetic moment, but the charge and magnetic moment are the opposite of those of an ordinary atom.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.