Definition of "water line" [wa•ter line]

• The line on the hull of a ship to which the surface of the water rises. (noun)
• Any of several lines parallel to this line, marked on the hull of a ship, and indicating the depth to which the ship sinks under various loads. (noun)
• A line or stain, as one left on a seawall, indicating the height to which water has risen or may rise; a watermark. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "And that went better, for I holed her on the water line and that shell burst inside."
• "And this time it went well, because I holed her on the water line between the gun and the conning tower, and our third shot burst beside the gun, so that when the smoke cleared there was nobody standing up on deck to serve that gun."
• "It swung up smoothly and the breech clanged home, and I laid her on the water line below the conning tower."