History of measurementThe earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. Often such systems were closely tied to one field of use, so that volume measures used, for example, for dry grains were unrelated to those for liquids, with neither bearing any particular relationship to units of length used for measuring cloth or land.
Standard (metrology)In metrology (the science of measurement), a standard (or etalon) is an object, system, or experiment that bears a defined relationship to a unit of measurement of a physical quantity. Standards are the fundamental reference for a system of weights and measures, against which all other measuring devices are compared. Historical standards for length, volume, and mass were defined by many different authorities, which resulted in confusion and inaccuracy of measurements.
Chain (unit)The chain (abbreviated ch) is a unit of length equal to 66 feet (22 yards), used in both the US customary and Imperial unit systems. It is subdivided into 100 links. There are 10 chains in a furlong, and 80 chains in one statute mile. In metric terms, it is 20.1168 m long. By extension, chainage (running distance) is the distance along a curved or straight survey line from a fixed commencing point, as given by an odometer. The chain has been used for several centuries in England and in some other countries influenced by English practice.
League (unit)A league is a unit of length. It was common in Europe and Latin America, but is no longer an official unit in any nation. Derived from an ancient Celtic unit and adopted by the Romans as the leuga, the league became a common unit of measurement throughout western Europe. Since the Middle Ages, many values have been specified in several countries. It may have originally represented, roughly, the distance a person could walk in an hour. Ancient Roman units of measurement The league was used in Ancient Rome, defined as 11⁄2 Roman miles (7,500 Roman feet, modern 2.
TonTon is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of mass. Confusion can arise because ton can mean the long ton, which is the short ton, which is the tonne, also called the metric ton, which is 1,000 kilograms (about 2,204.6226218 pounds) or 1 megagram. Its original use as a measurement of volume has continued in the capacity of cargo ships and in terms such as the freight ton and a number of other units, ranging from in capacity.
Korean units of measurementKorean units of measurement, called cheokgwan-beop () or cheokgeun-beop () in Korean, is the traditional system of measurement used by the people of the Korean peninsula. It is largely based on the Chinese system, with influence from Japanese standards imposed following its annexation of the Korean Empire in 1910. Both North and South Korea currently employ the metric system. Since 2007, South Korea has criminalized the use of Korean units in commercial contexts but informal use continues, especially of the pyeong as a measure of residential and commercial floorspace.