The United States customary system (also called American system) is a system of measurement commonly used in the United States. The U.S. customary units have roots with the imperial units, which were used in the British Empire. Many U.S. units are virtually identical to their imperial counterparts, but the U.S. customary system developed from English units in use before the imperial system was standardized in 1824, and there are several numerical differences from the imperial system.
The vast majority of U.S. customary units have been defined in terms of the meter and the kilogram since...