\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.