<P> In its modern form , it consists of a set of electromechanical base units including metre for length , kilogram for mass , second for time and ampere as an electrical unit , and a few others , which together with their derived units , can measure any useful quantity . Metric system may also refer to other systems of related base and derived units defined before the middle of the 20th century , some of which are still in limited use today . </P>
<P> In its modern form , it consists of a set of electromechanical base units including metre for length , kilogram for mass , second for time and ampere as an electrical unit , and a few others , which together with their derived units , can measure any useful quantity . Metric system may also refer to other systems of related base and derived units defined before the middle of the 20th century , some of which are still in limited use today . </P>
standard unit of distance in the metric system
standard unit of distance in the metric system
metre
metre