Quart (qt)

Two pints. A staple retail milk and wholesale liquid standard.

A quarter of a gallon, two pints, and the quiet workhorse of British domestic measurement. Milk was delivered by the quart, medicines were dispensed in quart bottles, and tavern jugs were made to the measure. Its name is simply the Latin quartus, a fourth, and it is one of the few English units whose etymology says exactly what the unit does. The quart is also the second half of minding your Ps and Qs, the pints and quarts chalked on an alehouse slate against a customer’s name until payday, and the impossibility of getting one into a pint pot has been proverbial since the nineteenth century. Like the pint, the imperial quart is larger than the American, at 1.14 litres against 0.95, for the same reason: Britain redefined its gallon in 1824 and the United States did not.