What Does SI Prefix Mean?

The SI prefixes are a series of prefixes to units in the International System of Units, or SI. These can denote very small or very large amounts. They are most commonly used in computing to refer to storage space, such as bytes, even though storage is not an official SI unit.

Techopedia Explains SI Prefix

SI prefixes denote the amounts of SI units, commonly known as the metric system. They are based on powers of ten.