Breadcrumb Home > Dictionary > Index P ptosis: Meaning and Definition of Find definitions for: pto•sis Pronunciation: (tō'sis), [key] — n. Pathol. a drooping of the upper eyelid. prolapse or drooping of any organ. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ptosis (Thesaurus) ptomaine poisoning ptp. TrendingHere are the facts and trivia that people are buzzing about. The Book of Philippians: Summary Current Events This Week: May 2023 Preamble of the United Nations Charter Queen Victoria Books of the Bible: New Testament Books in Order The 88 Recognized Constellations ✖ Related Content Daily Word Quiz: panache Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language