The gallon is a unit of volume in the imperial unit system with the symbol gal.
1 British imperial gallon is defined as 4.54609 litres or 277.4194 in³.
The term gallon derives directly from the Old Northern French term 'galun' which means 'liquid measure'. The origin of the word prior to this is still unknown. It originated as the base of the system for measuring wine and beer in the UK and has now been adopted across the world and there are similar versions in the US and associated states (although they measure slightly differently).
The US dry pint is a unit of volume in the US customary system with the symbol dry pt.
1 US dry pint is equal to 1/8 of a dry gallon. This is equal to 1/2 US dry quart or 33.6003125 in³.
The dry pint was derived from the the British corn gallon which was 1/8 the standard 'Winchester' bushel or corn. This was the equivalent of 268.8 in³ when in dry form.