IUPAC definition : Particular quantity, defined and adopted by convention, with which other quanitities
of the same kind are compared in order to express their magnitudes relative to that
quantity. Units have conventionally assigned names and symbols.;
Particular quantity, defined and adopted by convention, with which other quanitities
of the same kind are compared in order to express their magnitudes relative to that
quantity. Units have conventionally assigned names and symbols.