/ Dictionary / Index P peptic ulcer: Meaning and Definition of Find definitions for: pep'tic ul'cer Pronunciation: [key] — Pathol. Pathol. an erosion of the mucous membrane of the lower esophagus, stomach, or duodenum, caused in part by the corrosive action of the gastric juice. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. peptic peptidase Related Content Daily Word Quiz: modify Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language