An Etymological Dictionary of Astronomy and Astrophysics

In a system composed of one celestial body orbiting another, the synchronization of the orbital and rotational motions of the two bodies under the action of → tidal forces. For example, Pluto is tidally coupled to its moon Charon. As for the → Earth-Moon system,
billions of years from now, the Earth and the Moon will have the same period of rotation, and these will also exactly equal the orbital period of the Moon around the Earth. → tidal friction.

See also: → tidal; → coupling.