Term: dimensionless quantities
https://doi.org/10.1351/goldbook.D01742

Definition:
Quantities of dimension one, or numerical quantities, are numbers which may be integers (or exceptionally half-integers) when obtained by counting (e.g. number of molecules, quantum numbers, ...), rational numbers such as ratios, factors and fractions when obtained as ratios of two quantities of the same kind or real numbers when obtained by taking logarithms (e.g. absorbance, power levels, ...).

Related Terms:
1) absorbance (http://doi.org/10.1351/goldbook.A00028).
2) power (http://doi.org/10.1351/goldbook.P04792).

Source: Green Book, 2nd ed., p. 77 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Citation: 'dimensionless quantities' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.D01742

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