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

Cubans have dismissed the move as a drop in the ocean of their needs.

From Barron's ● Oct. 9, 2026

Nick Dulvy, a professor and marine conservationist at Simon Fraser University in British Columbia, called it a “disaster” and said that biologically, the sharks are “the most sensitive species in the ocean to overfishing.”

From Salon ● Oct. 9, 2026

The ocean gives me somewhere to place thoughts that feel too large for my apartment.

From Los Angeles Times ● Oct. 9, 2026

Together, the genus and species names reflect what the researchers described as an almost mystical elvish landscape on the deep ocean floor.

From Science Daily ● Oct. 8, 2026

Even across the ocean, the madness seemed to be spreading: the papers said America would enter.

From "The Hiding Place" by Corrie ten Boom

Concerns about aquaculture extend far beyond the fate of the oceans.

From Los Angeles Times ● Oct. 9, 2026

The broadcaster, who turned 100 earlier this year, narrates the new six-part series exploring the darkest depths of the world's oceans, produced by the BBC Natural History Unit in Bristol.

From BBC ● Oct. 7, 2026

From August through October, meltwater and rainfall add mass to the oceans, pushing Earth's center of mass toward the South Pacific Ocean.

From Science Daily ● Oct. 7, 2026

The sea level is rising at a record pace, driven by warming oceans and glacier melt, according to a UN report.

From Barron's ● Oct. 2, 2026

Miraculously it survives the humidity and our moves, with only a few unwarranted archipelagos of gray mold dotting its oceans.

From "The Poisonwood Bible" by Barbara Kingsolver

Related Words

• sea
• tide