waterline

noun

wa·​ter·​line ˈwȯ-tər-ˌlīn 

ˈwä-

: a line that marks the level of the surface of water on something: such as

a(1)

: the point on the hull of a ship or boat to which the water rises

(2)

: a line marked on the outside of a ship that corresponds with the water's surface when the ship is afloat on an even keel under specified conditions of loading

b

: shoreline sense 1

Examples of waterline in a Sentence

We repaired the hull below the waterline.

Recent Examples on the Web

Above the shimmering waterline, a pair of slick gray dorsal fins emerge—a mother swimming alongside her child. —Hannah Towey, Condé Nast Traveler, 22 Apr. 2026

The drastic measures are necessary to keep the Powell waterline high enough to run the power-generation turbines without air getting into the system and causing damage, federal officials say. —ABC News, 22 Apr. 2026

The project also includes installation of major waterlines in partnership with the Placer County Water Agency. —Nicole Buss, Sacbee.com, 9 Apr. 2026

Leaves, pollen, insects, and debris accumulate on the water surface, while dirt settles along the pool floor and waterline. —Atharva Gosavi, Interesting Engineering, 27 Mar. 2026

Word History

First Known Use

circa 1625, in the meaning defined above

Phrases Containing waterline

• the waterline

Rhymes for waterline

• acridine
• alkaline
• andesine
• anodyne
• anticline
• arginine
• asinine
• atropine
• benzidine
• borderline
• byzantine
• calamine

Kids Definition

waterline

noun

wa·​ter·​line ˈwȯt-ər-ˌlīn 

ˈwät-

: a line marked on the outside of a ship that matches the surface of the water when the ship floats evenly