Attribute of a phenomenon, body or substance that may be distinguished qualitatively
and determined quantitatively.
The term quantity may refer to a quantity in a general sense, for example length,
mass, or to a particular quantity, for example length of a particular rod, mass of
a specified object.
The term kind-of-quantity refers to the abstract concept of a quantity common to a group of related quantities.
PAC, 1996, 68, 957
(Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations
on page 987
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook