The imperial system of units, imperial system or imperial units is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments.
Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system the base unit for length is the metre.
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales.
Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, nations have transitioned from their local and traditional units of measurement to the metric system. This process began in France during the 1790s, and continues more than two centuries later—with the modern SI system—as the metric system has not been fully adopted in all countries and sectors.
Tael, also known as the tahil and by other names, can refer to any one of several weight measures used in East Asia and Southeast Asia. It usually refers to the Chinese tael, a part of the Chinese system of weights and currency. The Chinese tael was standardized to 50 grams in 1959.
Chinese units of measurement, known in Chinese as the shìzhì, are the traditional units of measurement of the Han Chinese. Although Chinese numerals have been decimal (base-10) since the Shang, several Chinese measures use hexadecimal (base-16). Local applications have varied, but the Chinese dynasties usually proclaimed standard measurements and recorded their predecessor's systems in their histories.
Long ton, also known as the imperial ton or displacement ton, is the name for the unit called the "ton" in the avoirdupois system of weights or Imperial system of measurements. It was standardised in the 13th century. It is used in the United Kingdom and several other Commonwealth of Nations countries alongside the mass-based metric tonne defined in 1799, as well as in the United States for bulk commodities.
Shaku or Japanese foot is a Japanese unit of length derived from the Chinese chi, originally based upon the distance measured by a human hand from the tip of the thumb to the tip of the forefinger. Traditionally, the length varied by location or use, but it is now standardized as 10/33 m, or approximately 30.3 centimeters (11.9 in).
Metrication is the process of introducing the International System of Units, also known as SI units or the metric system, to replace a jurisdiction's traditional measuring units. Although U.S. customary units have been defined in terms of metric units since the 19th century, the United States is one of only three countries that, as of 2022, have not officially adopted the metric system as the primary means of weights and measurements.
A system of measurement is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Systems of measurement in use include the International System of Units or SI, the British imperial system, and the United States customary system.
The chi is a traditional Chinese unit of length. Although it is often translated as the "Chinese foot", its length was originally derived from the distance measured by a human hand, from the tip of the thumb to the tip of the forefinger, and is similar to the ancient span. It first appeared during China's Shang dynasty approximately 3000 years ago and has since been adopted by other East Asian cultures such as Japan (shaku), Korea (ja/cheok), and Vietnam (thước). Its present value is standardized at around one-third metre, although the exact standards vary among the mainland of the People's Republic of China, its special administrative region of Hong Kong, and Taiwan.
The spread of metrication around the world in the last two centuries has been met with both support and opposition.
Metrication in Canada began in 1970 and ceased in 1985. While Canada has converted to the metric system for many purposes, there is still significant use of non-metric units and standards in many sectors of the Canadian economy and everyday life today. This is mainly due to historical ties with the United Kingdom, the traditional use of the imperial system of measurement in Canada, proximity to the United States, and strong public opposition to metrication during the transition period.
Metrication in Australia effectively began in 1966 with the conversion to decimal currency under the auspices of the Decimal Currency Board. The conversion of measurements—metrication—commenced subsequently in 1971, under the direction of the Metric Conversion Board and actively proceeded until the Board was disbanded in 1981.
Traditional Japanese units of measurement or the shakkanhō is the traditional system of measurement used by the people of the Japanese archipelago. It is largely based on the Chinese system, which spread to Japan and the rest of the Sinosphere in antiquity. It has remained mostly unaltered since the adoption of the measures of the Tang dynasty in 701. Following the 1868 Meiji Restoration, Imperial Japan adopted the metric system and defined the traditional units in metric terms on the basis of a prototype metre and kilogram. The present values of most Korean and Taiwanese units of measurement derive from these values as well.
A cun, often glossed as the Chinese inch, is a traditional Chinese unit of length. Its traditional measure is the width of a person's thumb at the knuckle, whereas the width of the two forefingers denotes 1.5 cun and the width of four fingers side-by-side is 3 cuns. In this sense it continues to be used to chart acupuncture points on the human body in various uses of traditional Chinese medicine.
Metrication in the Republic of Ireland happened mostly in the 20th century and was officially completed in 2005, with a few exceptions.
Taiwanese units of measurement are the customary and traditional units of measure used in Taiwan. The Taiwanese units formed in the 1900s when Taiwan was under Japanese rule. The system mainly refers to Japanese system. The measurement refers to the traditional size of a Japanese flooring mat called a Tatami mat which were positioned to completely cover the floor of traditional Japanese homes, therefore it became a convenient measurement tool as mat area was standardised hundreds of years ago. In Taiwan the measurement units are pronounced in Taiwanese Hokkien and Hakka before the World War II and adopted by the Mandarin speaking immigrants from China in 1949. Today, the Taiwanese units are used exclusively, in some cases alongside official SI units, and in other cases they have been replaced by SI.
The following outline is provided as an overview of and topical guide to the metric system – various loosely related systems of measurement that trace their origin to the decimal system of measurement introduced in France during the French Revolution.
The imperial and US customary measurement systems are both derived from an earlier English system of measurement which in turn can be traced back to Ancient Roman units of measurement, and Carolingian and Saxon units of measure.
