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 mass of salt water covering most of the earth 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 of ocean

• sea

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

Since Ganymede likely hides a vast ocean beneath its ice shell, understanding how its magnetic field survives could offer clues about potentially habitable environments elsewhere in the solar system. —Rupendra Brahambhatt, Interesting Engineering, 10 May 2026

The initial investigation suggested that on May 2, one service member jumped into the ocean to save the other service member who had fallen into the water off the sea cliffs by the Cap Draa Training Area outside of Tan-Tan, Morocco. —Molly Parks, The Washington Examiner, 10 May 2026

For Cousteau, the biological health of the ocean and the cultural health of humanity are the same struggle. —Christopher Elliott, Forbes.com, 10 May 2026

However, the weeks leading up to and immediately following summer are wonderful times to visit for still-warm weather, mild ocean temperatures, smaller crowds, and more affordable rentals. —Cameron Beall, Southern Living, 10 May 2026

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

Rhymes for ocean

• lotion
• notion
• potion
• commotion
• demotion
• devotion
• emotion
• laotian
• promotion
• locomotion

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