Tides, The is a body of water that is surrounded by land. The word “tides” is often used to refer to the rise and fall of the water level in the ocean, but it can also be used to refer to the rise and fall of the water level in any large body of water, such as a lake or river. The water level in the ocean is affected by the gravitational pull of the moon and the sun, as well as the wind and the rotation of the earth. The water level in a lake or river is affected by the same factors, but to a lesser extent.