water line

or wa·ter·line

noun

Nautical. the part of the outside of a ship's hull that is just at the water level.
Naval Architecture. any of a series of lines on the hull plans of a vessel representing the level to which the vessel is immersed or the bottom of the keel.Compare load line, Plimsoll line.
the line in which water at its surface borders upon a floating body.

water level(def 2).
Also called watermark. a line indicating the former level or passage of water: A water line all around the cellar served as a reminder of the flood.
a pipe, hose, tube, or other line for conveying water.

Origin of water line

First recorded in 1615–25

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for water line

Historical Examples of water line

It left the ship glistening from trucks to water-line, and with darkened sails.
The Nigger Of The "Narcissus"
Joseph Conrad
"It may be a low-lying cloud on the water-line of the horizon," Teddy added.
Boy Scouts on Hudson Bay
G. Harvey Ralphson
The lance tore through just above the water-line of Red Dick's steamer.
Sonnie-Boy's People
James B. Connolly
The water-line is strewn with cast-off salmon heads and entrails.
Over the Rocky Mountains to Alaska
Charles Warren Stoddard
Presently it was seen that she had been hit below the water-line.
Lectures on the French Revolution
John Emerich Edward Dalberg-Acton

British Dictionary definitions for water line

water line

noun

a line marked at the level around a vessel's hull to which the vessel will be immersed when afloat
a line marking the level reached by a body of water

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012