The serum of the blood. Obsolete.

Watery fluid in an animal body; the serous or watery part of blood or milk, serum; frequently plural in 17–18th centuries = watery humours.

transferred and figurative. Blood; a fluid, real or imaginary, likened to the blood of animals. †Formerly, the serum of the blood. Now chiefly poetic.

Watery animal fluid, normal or morbid; spec. blood-serum, the greenish yellow liquid which separates from the clot when blood coagulates.

The whitish or colourless part of the blood; serum, plasma. Obsolete.

= serum, n. a.