Definition of "atavism" []

• The reappearance of a characteristic in an organism after several generations of absence, usually caused by the chance recombination of genes. (noun)
• An individual or a part that exhibits atavism. Also called throwback. (noun)
• The return of a trait or recurrence of previous behavior after a period of absence. (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.

• "The term atavism is employed to express the reappearance of characters, physical or psychical, in the individual, or in the race, which are supposed to have been possessed at one time by remote ancestors."
• "No clear conception as to its true nature had been formulated, and even the propriety of designating the observed phenomena by the term atavism seemed doubtful."
• "The origin (perhaps rather the distinction) of species is accounted for principally by the last named law, by means of which Eimer also explains the so-called atavism or reversion."