释义
n.
a unit of activity or potency for vitamins, hormones, or other substances, defined individually for each substance in terms of the activity of a standard quantity or preparation
国际（标准）单位，国际生物（标准）单位（维生素、荷尔蒙及其他物质的效应单位，根据各物质的标准量或标准制剂的效应分别设定）。