Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
the theory that all material objects and substances are composed of atoms, and that various phenomena are explained by the properties and interactions of these atoms
Used by arrangement with John Wiley & Sons, Inc.
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The physical theory of the structure, properties, and behavior of the atom.