The tidal stream is the horizontal flow of water which is caused by the rise and fall of the tide.
The direction of the tidal stream is called “set” and its speed is called “drift”.
In a harbor we call the tidal stream the flood stream, when the tide is rising, and the ebb stream, when the tide is falling.
Offshore we use the name in accordance with which direction the tidal stream is flowing towards
e.g. “south going stream” or “the stream is setting 180 degrees”.
A good indication of the set of the stream is given by ships at anchor or moored buoys.
Note that water which is driven mainly by the prevailing winds are called currents.