serum

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The clear yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot.
• noun Blood serum from the tissues of immunized animals, containing antibodies and used to transfer immunity to another individual.
• noun Watery fluid from animal tissue, such as that found in edema.
• noun Whey.

from The Century Dictionary.

• noun The blood-serum of an animal which has been rendered immune against some disease by injections of increasing quantities of the micro-organism of such disease; antitoxin. See serum diagnosis and immunity, 5.
• noun An antidiphtheritic serum.
• noun The thin part of milk separated from the curd and oil; whey. Also called serum lactis.
• noun The clear pale-yellow liquid which separates from the clot in coagulation of the blood; blood-serum.
• noun Any serous liquid, as chyle or lymph.

from the GNU version of the Collaborative International Dictionary of English.

• noun The watery portion of certain animal fluids, as blood, milk, etc.
• noun A thin watery fluid, containing more or less albumin, secreted by the serous membranes of the body, such as the pericardium and peritoneum.
• noun 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.
• noun 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.
• noun (Physiol. Chem.) an albuminous body, closely related to egg albumin, present in nearly all serous fluids; esp., the albumin of blood serum.
• noun (Physiol. Chem.) paraglobulin.
• noun (Physiol. Chem.) the whey, or fluid portion of milk, remaining after removal of the casein and fat.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The clear yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot. Also called blood serum.
• noun Blood serum from the tissues of immunized animals, containing antibodies and used to transfer immunity to another individual, called antiserum.
• noun A watery fluid from animal tissue, especially one that moistens the surface of serous membranes or that is exuded by such membranes when they become inflamed, such as in edema or a blister.
• noun The watery portion of certain animal fluids, as blood, milk, etc; whey.
• noun skincare An intensive moisturising product to be applied after cleansing but before a general moisturiser.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an amber, watery fluid, rich in proteins, that separates out when blood coagulates