D defs.my
Entry 1 sense Webster, 1913

Zymogen

· Zym·o·gen · IPA
01 n. A mother substance, or antecedent, of an enzyme or chemical ferment; -- applied to such substances as, not being themselves actual ferments…
  1. 1.
    A mother substance, or antecedent, of an enzyme or chemical ferment; -- applied to such substances as, not being themselves actual ferments, may by internal changes give rise to a ferment.(Physiol. Chem.)
    “The pancreas contains but little ready-made ferment, though there is present in it a body, zymogen, which gives birth to the ferment.” — Foster.