No, there is not difference between ground and earth. IEEE Std 100 and NEC (based on US standards): “ground (earth) is defined as a conducting connection, whether intentional or accidental, by which an electric circuit or equipment is connected to the earth, or to some conducting body that serves in place of the earth”. ABB Switchgear Manual (based on European standards): refer to the term “earth as both, the earth as a place and the earth as a substance, e.g. humus, clay, sand, gravel, rock”.
Please notice that applications such as airplane or spaceship, there is not earth as a place or substance. However, the chassis is referred as ground (earth) for purposes of an equipotential surface.
