Imperial units or the imperial system is a system of units,first defined in the British Weights and Measures Act of 1824,later refined (until 1959) and reduced. Systems of imperial unitsare sometimes referred to as foot-pound-second, after the baseunits of length, mass and time. The units were introduced in theBritish Empire, excluding the then already independent UnitedStates. As of 2008, all countries that used the imperial systemhave become officially metric, except for the United States, Burmaand Liberia, however some other countries have laws mandating orpermitting other systems of measurement, such as the UnitedKingdomwhich still uses many imperial measures, such as miles andyards for road signs, lb/oz, pints, etc. for many products, andalso uses inches and barleycorns for clothing and shoe sizesrespectively.according to
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