Mode

The mode is the most commonly occurring value in a set of numbers. A dataset can have one mode, several modes (bimodal/multimodal), or none if every value is unique. It is the only measure of central tendency that also works for non-numeric (categorical) data — for example, the most common shoe size sold.

Example: In 3, 7, 7, 7, 9, 12 the mode is 7 (it occurs three times).