- incentive stock option.
- International Organization for Standardization.
- the numerical exposure index of a photographic film under the system adopted by the International Organization for Standardization, used to indicate the light sensitivity of the film's emulsion.
- a combining form meaning “equal,” used in the formation of compound words: isochromatic; in chemistry, used in the names of substances which are isomeric with the substance denoted by the base word: isocyanic acid.
- International Organization for Standardization
- equal or identical
- indicating that a chemical compound is an isomer of a specified compound
