potential, potential difference, voltage, volts

Voltage means potential difference.  So when someone says, "The voltage of that power line over yonder is at 10kV."  What they mean is that the potential to which the wire itself is set is 10kV ABOVE the potential of the earth or ground.  Typically we take ground to be zero volts, but the 10kV has to be in reference to something standard.  Otherwise, it makes NO SENSE to say something is just at "blah" volts, unless it's in reference to something everyone listening understands what the implied reference is.  Therefore, people who don't REALLY know what they're talking about in say a scientific situation where everyone should be on the same knowledgable page should make sure to include to what their potential is referencing.

ALSO, volts is only the unit of potential and thus potential difference (voltage), SO you cannot interchange the words to hope for the same meaning in what you present.