Term: dimension https://doi.org/10.1351/goldbook.D01741 Definition: Product of powers of the base dimensions (the dimensions attributed to the base quantities of a system) which parallels the expression of the quantity in terms of the base quantities. When all the exponents of the base dimensions are zero the quantity has the dimension one and is often called dimensionless. Source: PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 969 (https://doi.org/10.1351/pac199668040957) Citation: 'dimension' 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.D01741 License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.