metric system

A system of measurement based on the decimal system. It was first formalized in France at the end of the 18th century and by the 1830s was being widely adopted in Europe. In the UK, bills for its compulsory adoption were defeated in 1871 and 1907 and Imperial units remained supreme until 1963, when the yard was redefined as 0. 9144 metre and the pound as 0. 453 592 37 kilogram. The Metrication Board set up in 1969 failed to achieve its target of the metrication of British industry by 1975. However, the Weights and Measures Act (1985), the 1994 Amendment Order, and the 1994 Regulations took into account directives issued by the European Union. As a result certain traditional units such as the hundredweight, ton, pound, ounce, yard, foot, inch, gallon, bushel, square mile, cubic yard, and cubic foot were outlawed for purposes of trade. Finally, in January 2001, the UK adopted into law an EU directive making it illegal (with a few specified exceptions) to sell goods in any measures other than the gram, kilogram, millimetre, and metre. The pint (for milk and draught beer), the mile (for road traffic signs), and the acre (for land registration) are authorized without time limit. For all scientific purposes and many trade and industrial purposes the form of the metric system known as SI units is now in use. In the USA metrication has been even slower than in the UK.