serum
UK: ˈsɪərəm | US: ˈsɪrəm
n. 1. The clear, pale-yellow liquid that separates from blood when it clots, used in medical treatments and research.
n. 2. Any similar bodily fluid, such as lymph or amniotic fluid.
n. 3. A concentrated preparation of antibodies or other proteins derived from blood, used for immunity or therapy.
The word "serum" traces back to Latin serum, meaning "whey" (the watery part of milk). This reflects its original association with fluid separation. Over time, it was adopted into medical terminology to describe the liquid component of blood or other bodily fluids, retaining its core idea of a clear, separable substance. The suffix -um is a neutral noun ending in Latin, often used for scientific terms.
The lab technician analyzed the serum for antibodies.
Snake venom antiserum is derived from immunized animals.
After centrifugation, the blood sample separated into serum and clots.
She applied a facial serum to hydrate her skin.
Researchers studied the serum’s protein composition.