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.

---

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

---

mean sea level Scientific  

1. See under sea level

---

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

Maximum projected distant-source tsunamis could bring waves of 15 feet above mean sea level to the Santa Monica Pier and Marina del Rey and 32 feet at San Francisco’s Ocean Beach.

From Los Angeles Times • Jul. 30, 2025

The Met Office said the mean sea level pressure reading for England and Wales in November is the lowest ever, breaking a record that had stood since 1916.

From Washington Times • Nov. 2, 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

The datum plane generally used in maps is mean sea level, hence the elevations indicated would be the heights above mean sea level.

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

Related Words

• water level