Volume is the
quantity of
three-dimensional space enclosed by some closed boundary, for example, the space that a substance (
solid,
liquid,
gas, or
plasma) or shape occupies or contains. Volume is often quantified numerically using the
SI derived unit, the
cubic metre. The volume of a container is generally understood to be the capacity of the container, i. e. the amount of fluid (gas or liquid) that the container could hold, rather than the amount of space the container itself displaces.