The potential at a given position is a functional of the density, that is, given a particular density function and a point in space, one can compute a number which represents the potential of that point in space due to the specified density function.
The potential at a given position is a functional of the density. The density is. One can compute a number. This is given a particular density function in space. This is given a point in space. This number represents the potential of that point in space due to the specified density function.