Quart

A unit of volume equal to one quarter of a gallon. Its exact size differs among customary measurement systems.

Gallon: A unit of liquid volume whose size varies among measurement systems. Each quart is defined as one quarter of a gallon in the same system.
US customary units: A system of measurement used in the United States, including customary units of volume. Its liquid quart is one quarter of the US liquid gallon.
Cooking measurement: The use of standardized quantities to measure ingredients in food preparation. Recipes may specify quarts, but their measurement system determines the amount.
US liquid quart: A US customary unit of liquid volume equal to 32 US fluid ounces or about 0.946 liters. This is the quart most often meant in contemporary US recipes and packaging.
Pint: A unit of volume equal to half a quart in systems that divide a quart into two pints. Two pints make a quart in both US customary and imperial measures.
Imperial units: A system of units established in Britain in 1824 and historically used across the British Empire. Its quart is larger than the US liquid quart because the imperial gallon is larger.
Food labeling: The information displayed on food packaging about a product’s contents and characteristics. Container labels may state volume in quarts alongside other units.
Imperial quart: An imperial unit of volume equal to one quarter of an imperial gallon, about 1.137 liters. Its larger value shows why an unspecified quart can be ambiguous.
Cup (unit): A unit of volume commonly equal to one quarter of a US customary quart. Four US customary cups make one US liquid quart.
US dry quart: A US customary unit of dry volume equal to one quarter of a US dry gallon. It differs in size from the US liquid quart despite sharing the quart name.

Linked from 3 pages

Winchester measureBroader topic: Four Winchester quarts make a Winchester gallon, linking smaller measures to the system.