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

That allows the sea level to rise a little bit, “and it creates what we call a downwelling oceanic Kelvin wave,” said Jon Gottschalck, the Climate Prediction Center’s operational prediction branch chief.

From Los Angeles Times • Jun. 15, 2026

Playing at home, at 7,300 feet above sea level and before 80,000 or so rabid supporters, El Tri will be heavily favored to win.

From Salon • Jun. 11, 2026

Camp 4, which sits at 7,920m above sea level, is the highest.

From BBC • Jun. 10, 2026

The conditions, at almost 28,000 feet above sea level, were extreme.

From The Wall Street Journal • Jun. 1, 2026

The speed of sound, about 761 miles per hour at sea level in dry air at 59 degrees Fahrenheit, varied depending on temperature, altitude, and humidity.

From "Hidden Figures" by Margot Lee Shetterly

Related Words

• water level