unit of capacity in the U.S. Customary and the British Imperial Systems (British Imperial System) of measurement. In the United States the peck is used only for dry measure and is equal to 8 dry quarts (quart), or 537.6 cubic inches (8.810 litres). In Great Britain the peck may be used for either liquid or dry measure and is equal to 8 imperial quarts (2 imperial gallons), or one-fourth imperial bushel, or 554.84 cubic inches (9.092 litres). The peck has been in use since the early 14th century, when it was introduced as a measure for flour. The term referred to varying quantities, however, until the modern units were defined in the 19th century.