ˈsirəm, sometimes ˈsēr- or ˈser- noun
( plural serums -rəmz ; or se·ra -rə)
Usage: often attributive
Etymology: Latin, whey, watery fluid, serum; akin to Greek oros whey, serum, hormē rush, onset, assault, Sanskrit sarati it runs, flows
1. : the watery portion of an animal fluid remaining after coagulation:
a. : blood serum ; especially : immune blood serum that contains specific immune bodies (as antitoxins or agglutinins)
antitoxin serum
— compare vaccine
b. : whey
c. : a normal or pathological serous fluid (as in a blister)
2. : the watery part of a vegetable fluid ; specifically : the watery part of rubber latex on which the rubber floats after coagulation