waterline

1. A line formed by the surface of the water on the hull of a ship when she is afloat; any of a series of short lines marked on the hull to show where the waterline would be under different loadings
2. A horizontal line indicating the shape of an airfoil.
3. A line showing where the water has been.
4. The line formed by where the water level of a body of water currently is: where the water's surface currently meets the bank; it may move higher or lower depending on the weather, tide, or season. · Near-synonym: water's edge
5. The inner rim of the eyelid, just behind the lash line; primarily used in reference to the application of eyeliner.
6. A water pipeline.

الجمع waterlines