The mode is the data point that occurs more times than any other. A dataset can have one mode (unimodal), two (bimodal), more (multimodal), or none if every value is unique.
In academic performance data, the mode is rarely useful for individual results — a student's marks aren't really a "frequency distribution". It becomes useful for class-level analytics: the mode of a question paper's marks reveals the most common scoring band, which often pinpoints which difficulty level the paper actually tested.
Mode is also the only one of the three classical averages (mean, median, mode) that works on non-numeric / categorical data — for example, "what is the most common grade earned in this class" is a mode question even though grades are letters, not numbers.