1. A gradual process in which something changes into a different and usually more complex or better form. See synonyms at development. 2a. The process of developing. b. Gradual development. 3. Biology a. Change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species. b. The historical development of a related group of organisms; phylogeny. 4. A movement that is part of a set of ordered movements. 5. Mathematics The extraction of a root of a quantity.
The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2000 by Houghton Mifflin Company. Published by the Houghton Mifflin Company. All rights reserved.