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.
The liquid gallon is a unit of volume in the US customary unit system and uses the symbol gal.
It is the most common use of the word gallon and is defined as 231 in³. It is made up of 4 quarts where there are 2 pints in a quart and 16 US fluid ounces in a US pint. There are therefore 128 US fluid ounces in a US gallon.
The term gallon is most prevalent when discussing and trading oil and fuel. To ensure consistency, the temperature of the liquid (typically petroleum or alcohol) is understood to be 15.6 °C (60 °F) at the time of measurement.