Meander Line

A line, often all ziggy, zaggy wibbly, and wobbly, that follows the border of (but does not enter) a body of water. It’s used to establish the location of the shoreline of that body of water for the purposes of selling the land adjacent to the water. Not to be confused with boundary lines between cities, counties, states, or nations which can actually run through the middle of a body of water to act as an official border between the two entities.