Source : Webster's Revised Unabridged Dictionary (1913)

Fibrinogen \Fi*brin"o*gen\, n. [Fibrin + -gen.] (Physiol. Chem.)
   An albuminous substance existing in the blood, and in other
   animal fluids, which either alone or with fibrinoplastin or
   paraglobulin forms fibrin, and thus causes coagulation.

Source : WordNet®

fibrinogen
     n : a protein present in blood plasma; converts to fibrin when
         blood clots [syn: {factor I}]