A differential gravitational force acting along an extended body as a result of the varying distance from a source of gravity to the different parts of the body, such as the force of the moon on the earth's oceans closest to and farthest from the moon.
"tidal force." YourDictionary, n.d. Web. 11 October 2018. <http://www.yourdictionary.com/tidal-force>.
tidal force. (n.d.). Retrieved October 11th, 2018, from http://www.yourdictionary.com/tidal-force
(plural tidal forces)
(physics) any of various gravitational forces acting on a body caused by variation in the distance between it and a source of a gravitational field; such forces due to the Moon are responsible for tides
English Wiktionary. Available under CC-BY-SA license.