/ Dictionary / Index A adaptive radiation: Meaning and Definition of Find definitions for: adap'tive radia'tion Pronunciation: [key] — Biol. Biol. the diversification of an ancestral group of organisms into a variety of related forms specialized to fit different environments or ways of life, each often further diversifying into more specialized types. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. adaptive optics Adar Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language