In classical mechanics, the gravitational potential at a location is equal to the work (energy transferred) per unit mass that is done by the force of gravity to move an object to a fixed reference location. It is analogous to the electric potential with mass playing the role of charge.
The reference location, where the potential is zero, is by convention
infinitely far away from any mass, resulting in a negative potential at
any finite distance.
In mathematics the gravitational potential is also known as the Newtonian potential and is fundamental in the study of potential theory.