What is voltage best described as?

Voltage is the electrical potential difference between two points — often described as the 'pressure' that pushes electric charge (current) through a circuit. It is measured in volts. A helpful water analogy: voltage is like the water pressure in a pipe, current is the rate of water flow, and resistance is the narrowing of the pipe that opposes flow. Without a voltage difference, no current flows. Distinguishing voltage (the push), current (the flow), and resistance (the opposition) — and how Ohm's law links them — is the foundation of the Electronics subtest.