/ Dictionary / Index P pleiotaxy: Meaning and Definition of Find definitions for: plei•o•tax•y Pronunciation: (plī'u-tak"sē), [key] — n. Bot. an increase in the normal number of parts. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pleio- pleiotropy 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