The cup is a unit of volume in the US customary unit system with the symbol cup.
It is equal to 1/2 US customary pint, 1/4 US customary quart and 1/16 US customary gallon. it is also equal to 236.5882365 millilitres.
Used primarily for cooking - the cup was adopted and established as a recognised unit of measure as it could be used by almost anyone in any kitchen. Due to the slight variants in design and size, it is rarely used as an accurate measure for important or critical materials, however it does represent a specific amount and can be used across many recipes to indicate what is needed.
The cubic millimetre (or cubic millimeter; US spelling) is a unit of volume and is derived from an SI unit with the symbol mm³.
One cubic millimetre is defined as the volume of a cube with sides one millimetre in length. It is the same as a microlitre. It is equal to 0.000000001m³.
There are 1 billion cubic millimetres in a cubic metre.