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 cubic centimetre (or cubic centimeter; US spelling) is a unit of volume and is derived from an SI unit with the symbol cm³.
There are 1000cm³ in 1 litre. 1 cubic inch is equal to 16.38706cm³.
The cubic centimetre is sometimes referred to as cc or ccm - for example when administering drugs in a liquid solution. This is due to its relatively small size.
It is also often used in the 'cc' form to express the size of a petrol or diesel engine and represents the total displacement volume of the engine.