There was a consensus, early in this thread, that every
difference of potentials is voltage but not every voltage is
a potential difference. In section 20.3 of Serway and
Faughn (5th edition), the authors derive the formula for
the delta_V in a straight conductor of length L moving
through a uniform magnetic field B directed
perpendicularly to v.
delta_V = B*L*v
Then they say "A potential difference is maintained across
the conductor as long as there is motion through the field."
I suppose the authors would disagree with our concuss
on the basis that "loads, such as light bulbs, do not
distinguish between potential and non-potential voltages."
Ludwik Kowalski