The term 'of an ocean motion' can be summarized by the word 'TIDAL'. TIDAL is an adjective that describes the periodic rise and fall of the sea level due to the gravitational pull of the moon and sun. This phenomenon is caused by the gravitational attraction between the Earth, moon, and sun, which causes the oceans to bulge outward in the direction of the moon and sun. The result is two high tides and two low tides each day.