Philosophy The ancient theory of Democritus, Epicurus, and Lucretius, according to which simple, minute, indivisible, and indestructible particles are the basic components of the entire universe.
Philosophy A theory according to which social institutions, values, and processes arise solely from the acts and interests of individuals, who thus constitute the only true subject of analysis.
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.