water line

American  

[waw-ter lahyn] / ˈwɔ tər ˌlaɪn /

Or waterline

noun

1. Nautical. the part of the outside of a ship's hull that is just at the water level.

2. 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.

3. the line in which water at its surface borders upon a floating body.

4. water level.

5. 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.

6. a pipe, hose, tube, or other line for conveying water.

7. waterline, the slightly wet inner rim of skin between the upper or lower eyelashes and the eye, especially with reference to the use of eyeliner.

   Apply pencil eyeliner to your upper and lower waterlines.

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water line British  

noun

1. a line marked at the level around a vessel's hull to which the vessel will be immersed when afloat

2. a line marking the level reached by a body of water

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Etymology

Origin of water line

First recorded in 1615–25

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Example Sentences

See Examples For:

water line

The water line is dropping around 20 to 22 centimetres a day.

From Barron's ● Oct. 4, 2026

"Turning olivine into carbonate can leave silica behind, and we see more of that silica in rocks that sat below the water line."

From Science Daily ● Sep. 30, 2026

The walls of the valley at this point are steep, reaching up to 50m above the water line.

From BBC ● Aug. 28, 2026

On Friday, the department closed several restrooms after the rough ocean damaged the water line and meter serving them.

From Los Angeles Times ● Aug. 2, 2026

Perhaps it was an old water line from the aqueducts.

From "The Mark of Athena" by Rick Riordan

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