In this course, we will only use ``potential energy''. In
electromagnetism, ``potential'' is defined as potential energy per
charge, often designated as 
, so it's different from potential
energy by a factor of 
. Confusingly, sometimes ``potential'' is
loosely used to mean the same thing as ``potential energy''; in
quantum mechanics this is often the case. But in this course, we will
only consider the single quantity ``potential energy.''