Voltage is the measure of electromotive force across an object, basically telling us how much the electrons want to move from one point to another. Due to this, you don’t measure voltage *through* an object, you measure *across* an object, because you measure how much desire there is for the electrons to get from one side across to the other side.
There is also a longstanding debate on whether or not it’s voltage or current that is dangerous and we’re taking the stance of it’s both. It’s the current that kills but you can’t have current without voltage. But depending on the circumstances, a high voltage can be very safe while at other times, if there is low resistance, it is very dangerous. That’s why it’s complicated and that’s why people refuse to agree on things.
Potential difference - the energy required to move a unit charge through an element, measured in volts.
Fundamentals of Electric Circuits, 5th Edition by Charles K. Alexander and Matthew N. O. Sadiku
Ability of electric charge to do work in moving another charge. Measured in volt units.
Grob’s Basic Electronics, 11th Edition by Mitchel E. Schultz