Systeme International d’Unites [SI]« BACK TO DICTIONARY INDEX
(n.) An international metric system introduced in France in 1960. It defines a quantity with a single unit and uses exponents to indicate powers of 10. These factors are applied to units such as Hertz, seconds, or meters. In computing and digital media, a quantity of bytes is expressed as a power of 2 rather than 10. Applying this distinction, the prefix mega means 1000 if it refers to Hertz, but it means 1024 if it refers to bytes. The table below shows the SI prefix, the factor for each, and the decimal value.