Metric prefix
standardized prefix of the SI (Système International) for measurement units, indicating a multiple or fraction as a power of 10 or 1000
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decimal. Each prefix has a unique symbol that is prepended to any unit symbol. The prefix kilo, for example, may be added to gram to indicate multiplication by one thousand: one kilogram is equal to one thousand grams. The prefix milli, likewise, may be added to metre to indicate division by one thousand, so one millimetre is equal to one thousandth of a metre.
Decimal multiplicative prefixes have been a feature of all forms of the metric system, with six of these dating back to the system's introduction in the 1790s. Metric prefixes have also been used with some non-metric units. The SI prefixes are metric prefixes that were standardised for use in the International System of Units (SI) by the International Bureau of Weights and Measures (BIPM) in resolutions dating from 1960 to 2022. Since 2009, they have formed part of the ISO/IEC 80000 standard. They are also used in the Unified Code for Units of Measure (UCUM).
Begin with the source’s own compact description: “Metric prefix” is standardized prefix of the SI (Système International) for measurement units, indicating a multiple or fraction as a power of 10 or 1000. The dossier treats that line as a proposition to test through Metric, prefix and standardized, not as a finished interpretation.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Aug 11, 2026. The linked authority identifier is Q131299. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1960, 2022 and 2009.
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This entry incorporates text from “Metric prefix” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.