The Collaborative International Dictionary of English v.0.48:

Peptic \Pep"tic\ (p[e^]p"t[i^]k), a. [L. pepticus, Gr.
   peptiko`s. See Pepsin.]
   1. Relating to digestion; promoting digestion; digestive; as,
      peptic sauces.
      [1913 Webster]

   2. Able to digest. [R.]
      [1913 Webster]

            Tolerably nutritive for a mind as yet so peptic.
                                                  --Carlyle.
      [1913 Webster]

   3. (Physiol. Chem.) Pertaining to pepsin; resembling pepsin
      in its power of digesting or dissolving albuminous matter;
      containing or yielding pepsin, or a body of like
      properties; as, the peptic glands.
      [1913 Webster]

   peptic ulcer, (Med.) an erosion of the mucous membrane
      forming the lining of the stomach, duodenum, or lower
      esophagus, originally believed to be due mostly to the
      action of gastric juice. Recently, the bacterium
      Helicobacter pylori has been implicated as a causal
      agent in many peptic ulcers. In other cases, the use of
      non-steroidal antiinflammatory agents (NSAIDs) such as
      aspirin are believed to be to blame. Such ulcers may be
      treated with antibiotics or antisecretory agents that
      reduce stomach acidity, or both. Formerly believed to be a
      chronic illness that could only be managed, it is now
      viewed as a curable disease.
      [PJC]

WordNet (r) 3.0 (2006):

peptic ulcer
    n 1: an ulcer of the mucous membrane lining of the alimentary
         tract [syn: peptic ulcer, peptic ulceration]