ocean

American  

[oh-shuhn] / ˈoʊ ʃən /

noun

• oceans
  plural

1. any part of or the entirety of salt water that covers more than 70 percent of the earth's surface.

   Most of her adult life had been spent on the ocean, first on a fishing boat, then in the navy, now as a marine biologist.

2. any of the geographical divisions of the earth’s salt water, in particular, the five identified as the Pacific, Atlantic, Indian, Southern, and Arctic Oceans.

3. a vast expanse or quantity.

   oceans of opportunity;

   the ocean of people at Woodstock.

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ocean British  

/ ˈəʊʃən /

noun

1. a very large stretch of sea, esp one of the five oceans of the world, the Atlantic, Pacific, Indian, Arctic, and Antarctic

2. the body of salt water covering approximately 70 per cent of the earth's surface

3. a huge quantity or expanse

   an ocean of replies

4. literary the sea

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ocean Scientific  

/ ō′shən /

1. The continuous body of salt water that covers 72 percent of the Earth's surface. The average salinity of ocean water is approximately three percent. The deepest known area of the ocean, at 11,034 m (36,192 ft) is the Mariana Trench, located in the western Pacific Ocean.

2. Any of the principal divisions of this body of water, including the Atlantic, Pacific, Indian, and Arctic Oceans.

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Usage

The word ocean refers to one of the Earth's four distinct, large areas of salt water, the Pacific, Atlantic, Indian, and Arctic Oceans. The word can also mean the entire network of water that covers almost three quarters of our planet. It comes from the Greek Okeanos, a river believed to circle the globe. The word sea can also mean the vast ocean covering most of the world. But it more commonly refers to large landlocked or almost landlocked salty waters smaller than the great oceans, such as the Mediterranean Sea or the Bering Sea. Sailors have long referred to all the world's waters as the seven seas. Although the origin of this phrase is not known for certain, many people believe it referred to the Red Sea, the Mediterranean Sea, the Persian Gulf, the Black Sea, the Adriatic Sea, the Caspian Sea, and the Indian Ocean, which were the waters of primary interest to Europeans before Columbus.

Other Word Forms

Derived Forms

• interocean
  adjective
• oceanlike
  adjective

Inflected Forms

Nouns

• oceans
  plural

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Etymology

Origin of ocean

First recorded in 1250–1300; Middle English ocean(e), from Old French or directly from Latin ōceanus, special use of Ōceanus Oceanus, from Greek ōkeanós, Ōkeanós

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Explanation

You know that vast, wet expanse of blue that keeps crashing waves on the beach? That's the ocean. Atlantic, Pacific, Indian...these are just a few of the big oceans of the world. If Columbus hadn't sailed the ocean blue in 14 hundred ninety-two, America would have never been discovered. Home to sharks, mermaids, sailboats, and tsunami waves, the ocean makes up most of the planet Earth. But you can use ocean to describe anything similarly vast and limitless, like an endless ocean of fans at a rock concert.

Example Sentences

See Examples For:

ocean oceans

A ship that was once the fastest in the world and is longer than the Titanic will be sunk off the coast of Florida and turned into the world's largest artificial ocean reef.

From BBC ● Nov. 11, 2026

In 2015 a girlfriend and I spent a few months separated by an ocean, during a period when my depression was consuming me.

From Slate ● Nov. 11, 2026

Avoiding tariffs and ocean freight saved money, but domestic shipping brought the total to $1,230.

From The Wall Street Journal ● Nov. 11, 2026

The California Department of Forestry and Fire Protection’s teams in the Santa Cruz area warned that ocean conditions can change in an instant, with high tides flooding beaches and cutting off escape routes quickly.

From Los Angeles Times ● Nov. 10, 2026

Uncle Dutch says in summer he’d watch the waves of corn out in the field and all he could think about was the ocean and cool water and tropical breezes.

From "The Seven Wonders of Sassafras Springs" by Betty G. Birney

The additional greenhouse gases being added to the atmosphere have trapped additional heat and about 90% of that has been absorbed by the oceans.

From BBC ● Nov. 9, 2026

Marine snow plays an important role in Earth's carbon cycle, the natural movement of carbon among the atmosphere, oceans, land, and living organisms.

From Science Daily ● Nov. 9, 2026

Its research vessels are meticulously mapping the oceans, from the Mariana Trench to the Arctic.

From The Wall Street Journal ● Nov. 2, 2026

These changes to California’s climate are being driven by human-made emissions, and warming oceans are increasing the risk of humid heat events, he said.

From Los Angeles Times ● Oct. 30, 2026

Separated by oceans and continents, buffeted by very different intellectual winds, the two men had sailed to the same port.

From "The Gene" by Siddhartha Mukherjee

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Related Words

• sea
• tide

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