ocean

noun

ˈō-shən 

plural oceans

often attributive

1

a

: the whole body of salt water that covers nearly three fourths of the surface of the earth

The ocean covers most of our planet, regulates our weather and climate, absorbs vast amounts of carbon dioxide, provides most of our oxygen, and feeds much of the human population.

—National Oceanic and Atmospheric Administration

b

: any of the large bodies of water into which the great ocean is divided

the oceans of the world

2

: a very large or unlimited quantity or expanse

Could have made oceans of money.

—James Joyce

He would have oceans of time for his ride.

—P. G. Wodehouse

Jutting from an ocean of prairie, they [the Sangre de Cristo mountains] run north-south like an iguana spine …

—Skiing

Synonyms

• blue
• brine
• deep
• Neptune
• sea
• seven seas

Examples of ocean in a Sentence

We've sailed across hundreds of miles of ocean.

the Pacific and Indian oceans

Recent Examples on the Web

Over 1,300 buoys across oceans around the world measure water temperature, wind and wave height – all of which are essential for coastal warnings, as well as long-term forecasts. —Christine Wiedinmyer, The Conversation, 11 Feb. 2025

According to the tsunami warning, sea level fluctuations and strong ocean currents could pose a threat along coasts, beaches, in harbors and in coastal waters. —Saman Shafiq, USA TODAY, 9 Feb. 2025

Together, Toothless and Hiccup soar through the sky, barreling past rocky cliffs and roaring oceans and flying far above fierce battles as the music swells. —Matt Minton, Variety, 9 Feb. 2025

Based on all available data, there is a tsunami threat to Puerto Rico and the Virgin Islands as sea level fluctuations and strong ocean currents could be a hazard along coasts, beaches, in harbors and in coastal waters. —CNN, 8 Feb. 2025

Word History

Etymology

Middle English occean "the sea flowing around the land mass of the known world," borrowed from Anglo-French, borrowed from Latin Ōceanus, borrowed from Greek Ōkeanós, probably of pre-Greek substratal origin

Note: Preserved variants of Greek Ōkeanós, as Ōgḗn, Ōgenós, Ōgēnós, may indicate that the velar stop, whatever its original voicing, was palatalized (hence *ūkʸān-?)—strongly suggesting non-Indo-European origin. Old attempts to find an Indo-European origin (as a comparison with Sanskrit ā-śayāna- "lying on") are unconvincing.

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing ocean

• a drop in the ocean
• inter-ocean
• mid-ocean ridge
• ocean perch
• ocean sunfish
• open ocean

Kids Definition

ocean

noun

ˈō-shən 

1

: the whole body of salt water that covers nearly three fourths of the surface of the earth

2

: one of the large bodies of water into which the ocean is divided

oceanic

ˌō-shē-ˈan-ik

adjective