NOTE 1 – The division of the concept of quantity into several kinds of quantity is to some extent arbitrary. Examples:
• The quantities diameter, circumference, and wavelength, are generally considered to be quantities of the same kind, namely of the kind of quantity called length.
• The quantities heat, kinetic energy, and potential energy, are generally considered to be quantities of the same kind, namely of the kind of quantity called energy.

NOTE 2 – Quantities of the same kind within a given system of quantities have the same dimension. However, quantities of the same dimension are not necessarily of the same kind.
Examples: The quantities moment of force and energy are not of the same kind, although they have the same dimension. Similarly for heat capacity and entropy, as well as for relative permeability and mass fraction.

NOTE 3 – In English, the terms for quantities in the left half of the table in IEV 112-01-01, Note 1, are often used for the corresponding kinds of quantity. In French, the term “nature” is only used in expressions such as “grandeurs de même nature” (in English, “quantities of the same kind”).