For questions about the gravitational interaction between astronomical bodies. This tag often describes water currents, but can also be applied to planetary phenomena such as tidal locking and tidal heating.

The tag includes but is not limited to the influence of an astronomical body on an or other body of .

It may also describe other fluids and their interactions, tidal locking, tidal heating, and other large-scale planetary phenomena related to and .

The and tags may also be relevant.