\Se"rum\ (s[=e]"r[u^]m), n. [L., akin to Gr. ???, Skr.
s[=a]ra curd.] (Physiol.)
(a) The watery portion of certain animal fluids, as blood,
    milk, etc.
(b) A thin watery fluid, containing more or less albumin,
    secreted by the serous membranes of the body, such as the
    pericardium and peritoneum.
{Blood serum}, the pale yellowish fluid which exudes from the
   clot formed in the coagulation of the blood; the liquid
   portion of the blood, after removal of the blood
   corpuscles and the fibrin.
{Muscle serum}, the thin watery fluid which separates from
   the muscles after coagulation of the muscle plasma; the
   watery portion of the plasma. See {Muscle plasma}, under
   {Plasma}.
{Serum albumin} (Physiol. Chem.), an albuminous body, closely
   related to egg albumin, present in nearly all serous
   fluids; esp., the albumin of blood serum.
{Serum globulin} (Physiol. Chem.), paraglobulin.
{Serum of milk} (Physiol. Chem.), the whey, or fluid portion
   of milk, remaining after removal of the casein and fat.