The
gallon is a measure of
liquid capacity in both the
US customary units and the
British imperial systems of measurement. Three significantly different sizes are in current use: the
imperial gallon defined as
litres, which is used in the United Kingdom,
Canada, and some
Caribbean nations; the
US gallon defined as , which is used in the US and some
Latin American and Caribbean countries; and the least-used
US dry gallon defined as .