/ Dictionary / Index P pleiotropy: Meaning and Definition of Find definitions for: plei•ot•ro•py Pronunciation: (plī-o'tru-pē), [key] — n. Genetics. the phenomenon of one gene being responsible for or affecting more than one phenotypic characteristic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pleiotaxy Pleistocene Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language