[Coda]

Potential difference is also called voltage, because it's measured in volts, and it's almost always what you use.

You can consider absolute electric potential to be the potential difference between the source of the field and a point at infinity, but you never use absolute electric potential when discussing circuits.

And as I described a couple posts ago, all elements in a circuit cause a voltage drop across them. If you have a circuit with a battery and a light bulb, then you'll measure a greater voltage between the positive and negative terminals of the battery than you will between the light bulb and one terminal.