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

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

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

Temperatures in the area of the ocean used to calculate El Niño were already 2.41 degrees above baseline.

From Los Angeles Times ● Aug. 13, 2026

The ocean unit saw a 23% jump in revenue to $2 billion, supported by higher freight rates and volume growth of 4.1%, the shipping group said.

From The Wall Street Journal ● Aug. 13, 2026

Falling fish populations and reduced seafood production could undermine food security for billions of people around the world who depend on the ocean as an important source of nutrition.

From Science Daily ● Aug. 11, 2026

But Swiss Re, which serves as an insurer for insurance companies, noted that losses from natural disasters often increase in the second half of the year, mainly due to hurricanes in the North Atlantic ocean.

From Barron's ● Aug. 11, 2026

FAR, FAR OUT in the ocean, a sailboat drifted.

From "Nim’s Island" by Wendy Orr

The Danish shipping company upgraded its full-year guidance after both underlying Ebitda and Ebitda in the oceans unit came in ahead of expectations, the analysts say.

From The Wall Street Journal ● Aug. 13, 2026

With parts of the globe aflame in wildfires, deadly heat waves parking over cities, record hot oceans and a strengthening super El Niño, it seems like we’re baking through the hottest year on record.

From Los Angeles Times ● Aug. 10, 2026

Copernicus also said the world's oceans hit record-high temperatures for a second straight month in July, driven by marine heatwaves around Europe and a powerful El Nino taking shape in the Pacific.

From Barron's ● Aug. 10, 2026

The Chengjiang fossils preserve evidence of more than 200 types of animals that inhabited the oceans over 500 million years ago.

From Science Daily ● Aug. 4, 2026

Pull back again, and the blue oceans came into view, then other continents and countries—Congo, Sudan, Afghanistan, and Iraq—all looking deceptively calm.

From "Outcasts United: An American Town, a Refugee Team, and One Woman's Quest to Make a Difference" by Warren St. John

Related Words

• sea
• tide