For a conservative force F, a scalar field ϕ‎ such that F = ∇ϕ‎. If the domain of F is path-connected, then ϕ‎ is unique up to a constant. If, as is conventional, gravitational potential ϕ‎ is defined as gravitational potential energy per unit mass, then F = −∇ϕ‎, where F is the gravitational field.