Well, both. There is a valid term called “electric(al) tension” which means the same thing as electrical potential or voltage.
Thanks. In nearly 3 decades (including college) of being in the Power Systems side of Electrical Engineering, including time spent working at Electric Utilities, I’ve never heard voltage described as tension. Tension lines and slack spans were always described by pulling strain.
After a little internet searching, I find the description as you describe. Learned something new (actually quite old) :-)