Question

what is potential difference

Answer 1

we can not measure absolute potential at a point. so,we go for the difference by keeping a reference point standard. normally ground potential is used as difference.

Answer 2

No way... I think you messed up buddy. We can measure potential of a point if the intensity of the force field is known.
\[\int\limits_{a}^{\infty} F.dx= the potential at that point, a\]

Answer 3

potential at that point , a < if you want a difference then substract the lower from the higher one