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

"The ocean is an acoustic environment, and sharks are clearly tuned into it in ways we are only beginning to understand," Kajiura said.

From Science Daily ● Sep. 30, 2026

"The message is very clear. The ocean is changing rapidly," said Pierre Bahurel, director general of Mercator Ocean International, which runs the European Union's Copernicus Marine Service.

From Barron's ● Sep. 30, 2026

The research also demonstrates why studying shark hearing in the ocean can reveal information that is difficult to obtain in laboratory tanks.

From Science Daily ● Sep. 30, 2026

On the upper level will be a cafe that leads to the most picturesque setting in college basketball, a patio area where the ocean view of Malibu is stunning and mesmerizing.

From Los Angeles Times ● Sep. 27, 2026

An ocean teeming with sea life, from tiny coral polyps to massive whales to birds skimming the surface of the waves.

From "Clairboyance" by Kristiana Kahakauwila

They are normally found throughout tropical regions of the Pacific, Indian and Atlantic oceans, and usually nest along the coasts of Mexico, Nicaragua, Costa Rica and Panama.

From Los Angeles Times ● Sep. 25, 2026

Natural-fiber garments also shed microfibers that have been found in oceans and human lung tissue, can persist in the environment and have harmed marine organisms in laboratory studies.

From The Wall Street Journal ● Sep. 24, 2026

Across oceans, perhaps early humans did wonder at the hazier skies and unusually vivid sunsets.

From Science Daily ● Sep. 22, 2026

This measures how warm the key El Niño region is relative to the rest of the tropical oceans, meaning it takes into account the background warming caused by climate change.

From BBC ● Sep. 22, 2026

But the main thing to know is this: The whole time, from before any of those extinctions, from life’s origins until this minute, jellyfish have been there, pulsing their way across the oceans and back.

From "The Thing About Jellyfish" by Ali Benjamin

Related Words

• sea
• tide