Meaning of international unit

interna'tional u'nit

Pronunciation: [key]
— Pharm. Pharm.
  1. an internationally agreed upon standard, as measured by bioassay, to which samples of a substance, as a drug or hormone, are compared to ascertain their relative potency.
  2. the particular quantity of such a substance, which causes a specific biological effect. Abbr.: IU
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.