The amount of work electricity can do is described in terms of amperage and voltage.

Amperage (A) describes the quantity of charge carriers flowing in an electric current.

Current is a colloquial term that means amperage.

Amp hours (Ah) describe the quantity of available charge or charge used.

Voltage (V) describes the quantity of electromagnetic force in which charge carriers are being pushed in an electric current.

Voltage is always a relative measurement between two points.

Wattage (W) is a convenience unit to describe electricity that includes amps and voltage, multiplied together (watts = amps x volts).

Volts and amps can be traded for each other in a current, as long as the overall amount of work (Wattage), stays the same. This is often done through induction.

Power is a colloquial term that usually means wattage.

Circuits are closed loops that consists of a voltage source, a load, and a return path called ground or common.