Source : Webster's Revised Unabridged Dictionary (1913)

Transfusion \Trans*fu"sion\, n. [L. transfusio: cf. F.
   transfusion.]
   1. The act of transfusing, or pouring, as liquor, out of one
      vessel into another. --Howell.

   2. (Med.) The act or operation of transferring the blood of
      one man or animal into the vascular system of another;
      also, the introduction of any fluid into the blood
      vessels, or into a cavity of the body from which it can
      readily be adsorbed into the vessels; intrafusion; as, the
      peritoneal transfusion of milk.

Source : WordNet®

transfusion
     n 1: the introduction of blood or blood plasma into a vein or
          artery [syn: {blood transfusion}]
     2: the action of pouring a liquid from one vessel to another