Voltage is known as the potential difference within two points of a conducting wire containing a constant current of 1 ampere whenever the power dissipated between these points is 1 watt. Voltage can also be referred to as potential difference or electromotive force (EMF). It is the force that pushes the electrons through a wire and is usually referred to as electrical pressure. A volt is the amount of potential needed to cause 1 coulomb to produce 1 joule of work.
One other thing keep in mind is that voltage cannot flow. Voltage in an electrical circuit is like pressure in a water system. To say that voltage flows through a circuit is like saying that pressure flows through a pipe. Pressure can push water through a pipe, and it is correct to say that water flows through a pipe, but it is not correct to say that pressure flows through a pipe. The same is true for voltage. Voltage will push current through a wire, but voltage cannot flow through a wire. Voltage is often considered to be the potential to do something. For this reason it is frequently referred to as potential. Voltage needs to be present before current can flow, similar to how pressure must be present before water can flow. A voltage, or potential, of 120 volts is present at a common wall outlet, however there is no flow until some device is connected and a complete circuit exists. The same is true in a water system. Pressure is present, but water cannot flow until the valve is opened and a path is provided to a region of lower pressure. The letter E, which stands for EMF, or the letter V, which stands for volt, can be used to represent voltage in an algebraic formula.