Definition:Mode

Definition
Let $S$ be a set of quantitative data.

The mode of $S$ is the element of $S$ which occurs most often in $S$.

If there is more than one such element of $S$ which occurs equally most often, it is then understood that each of these is a mode.

If there is no element of $S$ which occurs more often (in the extreme case, all elements are equal) then $S$ has no mode

Also see

 * Definition:Measure of Central Tendency


 * Definition:Arithmetic Mean
 * Definition:Median (Statistics)