1. The dot on a number typically represents multiplication in mathematics. 2. For example, $3 \cdot 4$ means $3$ multiplied by $4$, which equals $12$. 3. Sometimes, a single dot above a variable denotes a derivative with respect to time in physics and calculus, such as $\dot{x}$ representing the rate of change of $x$ over time. 4. The specific meaning depends on the context, but commonly it indicates multiplication or a time derivative.