/ Dictionary / Index P pleon: Meaning and Definition of Find definitions for: ple•on Pronunciation: (plē'on), [key] — n. the abdomen of a crustacean. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pleomorphism pleonasm 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