System of units of measurement
OverviewHistoryMetric systemBritish imperial and US customary unitsNatural unitsNon-standard unitsUnits of currencyHistorical systems of measurement
In antiquity, systems of measurement were defined locally: the different units might be defined independently according to the length of a king''s thumb or the size of his foot, the length of stride, the length of arm, or maybe the weight of water in a keg of specific size, perhaps itself defined in hands and knuckles. The unifying characteristic is that there was some definition based on some standard. Eventually cubits and strides gave way to "customary units" to meet the needs of merch