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 acre-foot is a unit of volume in the US customary unit system with the symbol ac⋅ft.
It represents the volume contained in a box measuring 660 feet long, 66 feet wide and 1 foot deep. This can be thought of a box the size of an acre but 1 foot deep.
It is approximately the same volume as an 8 lane swimming pool; 25 metres in length, 3 metres deep and 16 metres wide (assuming lanes are 2 metres wide).
It is still used in the US despite its links to the much-outdated imperial system of units. For example a "rule of thumb" is that an average suburban family's annual water usage should be around 1 acre-foot. This is equal to just under 3.4 m³ daily.