Energy can be transferred from potential to kinetic and between objects.
Potential energy is stored energy--energy ready to go. A lawn mower filled with gasoline, a car on top of a hill, and students waiting to go home from school are all examples of potential energy.
Gravitational potential energy is the energy possessed by a body because of its elevation (height) relative to a lower elevation, that is, the energy that could be obtained by letting it fall to a lower elevation. For example, water at the top of a waterfall or stored behind a dam at a hydroelectric plant has gravitational potential energy.