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A physical system of units that expresses any given measurement using fundamental units of the metre, kilogram, and/or second (MKS).

Historically the MKS system of units succeeded the cgs system of units and laid the foundations for the International System of Units, which now serves as the international standard. Therefore the exact composition of the MKS system is a historical issue. As a matter of historical record the MKS system incorporated fundamental units other than the metre, kilogram, and second in addition to derived units. An incomplete list of the fundamental/derived units appears below. If the MKS system of units never had a governing body to rule on a standard definition then this list might depend on different conventions and different times.

• cycle (This dimensionless quantity became synonymous with the term "cycle per second" as an abbreviation. This circumstance confused the exact definition of the term cycle. Therefore the term "cycle per metre" became ill-defined. The cycle did not become an SI unit.)
• cycle per second [1]
• cycle per metre (This measure of wavenumber became ill-defined due to the abbreviation of "cycle per second" as "cycle".)

[edit] External links

• description of the MKS system
• description of the previous cgs system

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