serum  
noun [ C or U ] uk/ˈsɪə.rəm/ us/ˈsɪr.əm/  sera uk/ˈsɪə.rə/ us/ˈsɪr.ə/ serums
  (BLOOD)         
  血清
the thin yellowish liquid part of the blood 
  cholesterol levels in blood serum 血清中的胆固醇水平 
  免疫血清
serum taken from an animal's blood and put into a human in order to fight an infection or a poison
  an anti-venom serum 抗蛇毒血清 
   (BEAUTY PRODUCT)     
 美容液(美容产品中的一种物质,用于改善头发或皮肤,减少干燥情况)
a substance in beauty products that is designed to improve your hair or skin and make it less dry