The intersection of the hull and the surface of the water.

also water-line, 1620s, line where the water rises to on the hull of a ship afloat, from water (n.1) + line (n.).

Waterline is the level reached by the sea or a river that is visible as a line on a rock face, beach, or riverbank. High waterline is the point on the shore to which the tide normally rises. Low water [..]

(n) 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

        The waterline, is exactly what it says.  This is the location

A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).

The actual junction of the land and water at any instant. Also, the line along which the surface of the water touches a vessels' hull.

A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).

A term used in shipbuilding and aerospace manufacturing to define horizontal reference plane that passes through the ship or aircraft.

The level of water in the boiler.

The line formed on a vessels exterior where the water surface comes in contact with the hull.

The line where the hull of a ship meets the water's surface.

That line in which the surface of the water meets the ship's side at a specific draught. 2. Line painted round ship's side at approximate position of her load waterline.

The line painted on the side of the vessel at the water's edge to indicate the proper trim.

Where the water's surface meets the hull; as in: We painted our waterline blue to provide more eye appeal.

A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).

The line painted on the side of the vessel at the water’s edge to indicate the proper trim.

The line where the water comes to on the hull of a boat.

One of a number of horizontal lines on the hull of a ship indicating the surface of the water when the ship is under various loads.

The line where the water comes to on the hull of a boat. Design waterline is where the waterline was designed to be, load waterline is the waterline when the boat is loaded, and the painted waterline [..]

 Where the hull of a ship meets the surface of the water.

The line of the water's edge when the ship is afloat

the point to which a ship sinks in the water; a line painted on the hull showing the point to which the ship sinks when properly trimmed.

1. an imaginary and moving (But sometimes painted on (Actually, the painted stripe is the "Boot Top" or "Boot Stripe")) line circumscribing the hull that matches the surface of the [..]

The line where the water comes to on the hull of a boat. Design waterline is where the waterline was designed to be, load waterline is the waterline when the boat is loaded, and the painted waterline [..]

the imaginary line on the hull that marks the level of the water surface when the vessel is afloat. Some vessels have a waterline painted on or inscribed in the hull. FH2004 

The line marking the junction of water and land. See also HIGH WATER LINE, LOW WATER LINE, SHORELINE.

An artificial horizon line.

The point where the surface of the water meets the hull.

The line of water on the side of the canoe when it is afloat. The waterline will vary with the load.