sea level

American  

noun

1. the horizontal plane or level corresponding to the surface of the sea at mean level between high and low tide.

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sea level British  

noun

1. the level of the surface of the sea with respect to the land, taken to be the mean level between high and low tide, and used as a standard base for measuring heights and depths

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sea level Scientific  

1. The level of the ocean's surface. Sea level at a particular location changes regularly with the tides and irregularly due to conditions such as wind and currents. Other factors that contribute to such fluctuation include water temperature and salinity, air pressure, seasonal changes, the amount of stream runoff, and the amount of water that is stored as ice or snow.

2. ◆ The reference point used as a standard for determining terrestrial and atmospheric elevation or ocean depths is called the mean sea level and is calculated as the average of hourly tide levels measured by mechanical tide gauges over extended periods of time.

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Etymology

Origin of sea level

First recorded in 1800–10

Example Sentences

Sixty miles from Julian, I turn onto Bannister Road and bump north along a gravel track for three miles into the basin, to a parking lot 164 feet below sea level.

From Los Angeles Times • Apr. 7, 2026

Ocean warming and sea level rise are projected to continue for centuries.

From Barron's • Mar. 23, 2026

South Africa, at Johannesburg's Ellis Park - 1,753m above sea level - is England's next, imposing task.

From BBC • Mar. 14, 2026

All seven newly discovered species were collected using light traps in rainforest areas more than 1,500m above sea level in Uganda's Kibale National Park.

From Science Daily • Mar. 11, 2026

As we looked out of the windows Momma checked her notebook, then announced, “This is the Appalachia Mountains. We’re over six thousand feet above sea level, this is higher than we’ve ever been before.”

From "The Watsons Go to Birmingham" by Christopher Paul Curtis

Related Words

• water level