international unit

international unit

noun

Definition of INTERNATIONAL UNIT

: a quantity of a biologically active substance (as a vitamin) that produces a particular biological effect agreed upon as an international standard

First Known Use of INTERNATIONAL UNIT

1922

international unit

noun    (Medical Dictionary)

Medical Definition of INTERNATIONAL UNIT

: the amount of specific physiological activity of a standardized preparation (as of a vitamin) that is agreed upon as an international standard especially for comparison with other biologicals containing the substance in impure form or with a related biologically active substance; also : the amount of the biologically active substance in the standard amount of the preparation producing this activity

international unit

noun    (Concise Encyclopedia)

Any of several precision standards used in measuring physical quantities, such as mass, length, and time (see International System of Units), and also lighting systems, radiation processes, and pharmacology. The luminous intensity or candlepower of a light is expressed in candelas. The second is based on the frequency of radiation emitted by cesium-133 atoms. In radioactive decay, the international unit is the number of disintegrations per second in a sample. In pharmacology, the international unit is the quantity of a substance (vitamin, hormone, or toxin) that produces a specified effect when tested according to an internationally accepted procedure.