this is a sort of "stretching" that a body undergoes due to the differential gravitational attraction by another body. In fact, the gravitational attraction varies according to the distance of the various points of one body, from the attractor body. If two points are attracted with forces of different intensities, they undergo a reciprocal stretching force. The Tidal Force of the Moon is responsible for the periodic rising of the sea during the orbit of the Moon around the Earth.
A stretching force that is caused by the difference between gravitational forces on opposite sides of an object, such as a planet or moon. For example, because the Moon pulls on opposite sides of the Earth with different strengths, water on the Earth is pulled either toward or away from the Moon, resulting in the ocean tides. Elsewhere in the Solar System, the magnitude of gravitational force on Jupiter's moon Io is greatest on the side of Io that faces Jupiter and least on the back side. The difference between the two forces compresses and stretches Io, which in turn heats up Io's interior. As a result, Io is the most geologically active body in the solar system.
the difference in gravitational force between two points on an object caused by the gravity of another object; the tidal force often leads to a deformation of an object
The tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational field is not constant across a body's diameter.