The BIPM specifies twenty-four prefixes for the International System of Units (SI).
The first uses of prefixes in SI date back to the definition of kilogram after the French Revolution at the end … See more

Examples
• The mass of an electron is about 1 rg (rontogram).
• The mass of 1 litre of water is about 1 kg (kilogram). See more

Obsolete metric prefixes
Some of the prefixes formerly used in the metric system have fallen into disuse and were not adopted … See more

• Binary prefix
• E1 series (preferred numbers)
• Engineering notation
• Indian numbering system See more

The use of prefixes can be traced back to the introduction of the metric system in the 1790s, long before the 1960 introduction of the SI. The … See more

In written English, the symbol K is often used informally to indicate a multiple of thousand in many contexts. For example, one may talk of a … See more

• International Bureau of Weights and Measures (BIPM)
• SI prefixes at BIPM
• US NIST Definitions of the SI units: The twenty SI prefixes See more