The Dominant period is the most prominent period of a Period Window. It corresponds with the highest peak or deepest valley in the Period Window, depending on the selected period analysis method. 

The Prominent Periods Table displays an overview of the 20 most prominent periods in a Period Window. The top entry of this table is the Dominant period.

The Dominant period is not necessarily the true period (or exact period) of the object under analysis. Some peaks or valleys arise from aliasing, others may be harmonics of the main (fundamental) frequency, etc. Even if a period is a true period, it may not be significant. Peranso offers a series of tools to try to distinguish true periods from artifacts and to determine the significance level of a period.