The Metre-Kilogram-Second (MKS) of units is a physical system of units that expresses any given measurement using the three fundamental units of the Metre, Kilogram, and/or Second. The MKS system, widely known as the Metric System, has succeeded the CGS system. The MKS system served as the basis for the development of the International System of Units (abbreviated SI).
The metre, kilogram, second system of units, also known more briefly as MKS units or the MKS system, is a physical system of measurement based on the metre, kilogram, and second (MKS) as base units. Distances are described in terms of metres, mass in terms of kilograms and time in seconds. Derived units are defined using the appropriate combinations, such as velocity in metres per second. Some units have their own names, such as the newton unit of force which is defined as kilogram times metres per second squared.
The modern International System of Units (SI, from the French name Système international d'unités) was originally created as a formalization of the MKS system. The SI has been redefined several times since then and is now based entirely on fundamental physical constants, but still closely approximates the original MKS units for most practical purposes.
