the inactive precursor of pepsin, synthesized by the gastric glands of the stomach and converted to pepsin by hydrochloric acid
See pepsinogen in American Heritage Dictionary 4
(pĕp-sĭnˈə-jən)
noun
The inactive precursor to pepsin, formed in cells of the mucous membrane of the stomach and converted to pepsin by autocatalysis in the presence of hydrochloric acid.