Voltage is a fundamental concept in electromagnetism and circuit theory, defined as the electric potential difference between two points in an electric circuit. It quantifies the energy per unit of electrical charge and serves as the driving force that causes electric current to flow. Measured in volts, voltage indicates the amount of work required to move a unit of charge between two points within a system. The magnitude of the voltage potential determines the pressure or "push" applied to the charge, which subsequently dictates the flow rate of the current.