sea level
Americannoun
noun
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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.
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◆ 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.
Etymology
Origin of sea level
First recorded in 1800–10
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"The highest point above sea level in Kiribati - unless you climb a coconut tree - is two metres. No water, no land, no resources other than fish."
From BBC • Apr. 26, 2026
Planters started anew in central Florida, in Polk County and its surroundings, what’s known as the Ridge, the highest part of Florida, and the only part that was never below sea level, historically.
From Slate • Apr. 20, 2026
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
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
Despite the many trappings of civilization at Base Camp, there was no forgetting that we were more than three miles above sea level.
From "Into Thin Air" by Jon Krakauer
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.