Water pipe and Waterline

Water pipe noun - An oriental tobacco pipe with a long flexible tube connected to a container where the smoke is cooled by passing through water.

Waterline and water pipe are semantically related. In some cases you can use "Waterline" instead a noun phrase "Water pipe".

Waterline noun - A line corresponding to the surface of the water when the vessel is afloat on an even keel; often painted on the hull of a ship.

Water pipe and waterline are semantically related. You can use "Water pipe" instead a noun "Waterline".