Term: mode https://doi.org/10.1351/goldbook.M03958 Definition: The value of the variable occurring with the greatest frequency in the series of observations. A bimodal distribution is one which contains two maxima. The use of mode when reporting results of chemical analysis is generally not recommended. Related Terms: 1) variable (http://doi.org/10.1351/goldbook.V06600). 2) bimodal distribution (http://doi.org/10.1351/goldbook.B00644). Source: PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2202 (https://doi.org/10.1351/pac199062112167) Citation: 'mode' 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.M03958 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.