Main Entry: ¹se·rum

Pronunciation: \ˈsir-əm\

Function: noun

Inflected Form(s): plural serums or se·ra \-ə\

Etymology: Latin, whey, wheylike fluid; akin to Greek oros whey

Date: 1665

1 : the watery portion of an animal fluid remaining after coagulation: a (1) : blood serum (2) : antiserum b : whey c : a normal or pathological serous fluid (as in a blister)
2 : the watery part of a plant fluid