ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ noun
1.
a. : any of several lines that are marked upon the outside of a ship and correspond with the surface of the water when it is afloat on an even keel — see ship illustration
b. : any of various lines of a ship, model, or plan parallel with the surface of the water at various heights from the keel
2. : shoreline
3.
a. : the level represented by the uppermost limit of ground wholly saturated with water : the level of the water in soil : water table
b. : the desired or actual level of water (as in a boiler or tank)
4. : a line of stain marking a former passage or upper level of water
the flood left a waterline on housefronts and fences
waterlines from old leaks
5. : a line (as of piping or hose) for carrying water