What is the term for the part of a body of water that continuously moves in a specific direction?

The correct term for the part of a body of water that continuously moves in a specific direction is "current." A current refers to a directed flow of water, typically found in rivers, oceans, or lakes, and is characterized by its movement which can vary in speed and direction based on factors like wind, the layout of the land, and water temperature differences.

Waves, on the other hand, are not characterized by a directional flow in the same way currents are; instead, they represent the surface movement caused by wind and other factors. Tides refer to the periodic rise and fall of sea levels due to the gravitational pull of the moon and the sun, which is a cyclic phenomenon rather than a continuous one. Flow could be a general term used, but it does not specify the directional movement inherent in the concept of a current, making "current" the most precise term for a continuous directional movement in water.