| the gravitational pull exerted by a celestial body that raises the tides on another body within the gravitational field, dependent on the varying distance between the bodies. |
| tidal force n. Any of various small gravitational forces acting on an extended body as a result of the varying distance between the source of the gravitational force, such as the moon, and the different parts of the extended body, such as the earth's oceans closest to and farthest from the moon. |
| tidal force
A secondary effect of the gravitational forces between two objects orbiting each other, such as the Earth and the Moon, that tends to elongate each body along the axis of a line connecting their centers. Tidal forces are responsible for the fluctuation of the tides as well as for the synchronous rotation of certain moons as they orbit their planets. |