Daymark

daytime identifier of an aid to navigation

A daymark is a sign used to help people navigate in lakes, rivers, or the ocean. It is fixed, but does not meet the criteria of a lighthouse. Very often, it is there for orientation, or to regulate traffic.

Daymark on the eastern end of Jesse Island, in British Columbia
The "Kugelbake" (ball beacon) is a sight of the city of Cuxhaven in Germany.