Quantity - Numerically quantifiable property
of any entity or phenomena.
Mass, length, and electric charge are quantities.
'Type of wood' such as oak, pine, or ash is not numerically quantifiable and thus not a
quantity; however, 'volume of wood' which may be measured in cords or board feet units is a quantity.
- particular quantity - the
quantity of a particular phenomena, object, class of identical objects, or substance that has a specific associated value. Examples: the
diameter of my basketball, the velocity of light in a vacuum, the mass of a neutron,
the density of silicon, the temperature of the sun's surface.
- physical quantity - (parameter)
A particular property as represented and/or analyzed through mathematical relationships. The letter m often represents the physical quantity of mass in
mathematical equations.
- NIST
SI definition link