mean sea level

American  

[meen see lev-uhl] / ˈmin ˈsi ˈlɛv əl /

noun

1. Oceanography. the average height of the ocean's surface, as measured frequently and during all fluctuations of tides and atmospheric conditions over an extended time, usually a number of years.

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mean sea level British  

noun

1. (in the UK) the sea level used by the Ordnance Survey as a datum level, determined at Newlyn in Cornwall See sea level

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mean sea level Scientific  

1. See under sea level

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Example Sentences

Last year, the global mean sea level was around 11 centimetres higher than when satellite altimetry records began in 1993.

From Barron's • Mar. 23, 2026

In Redondo Beach, for instance, a near-shore tsunami could bring waves of up to 11 feet above mean sea level, compared to 9 feet possible coming from a distant earthquake.

From Los Angeles Times • Jun. 8, 2025

The last of the helicopter’s data transmissions sent every three minutes indicated it was traveling in a northwesterly direction at an altitude of 144 feet above mean sea level at 107 mph, the report said.

From Washington Times • Aug. 9, 2023

According to the World Meteorological Organization, global mean sea level rose by 4.5 millimeters per year between 2013 and 2022.

From Seattle Times • Apr. 17, 2023

This plane is usually mean sea level and the contours are numbered from this plane upward, all heights being elevations above mean sea level.

From Manual of Military Training Second, Revised Edition by Moss, James A. (James Alfred)

Related Words

• water level