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

• 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

He’s taught at FAU for about 20 years and goes out for regular jaunts in the ocean to tag sharks with transmitters so investigators can track their behavior. —Lois K. Solomon, Sun Sentinel, 5 July 2025

Over 90 million Americans swim in pools, lakes and oceans every year, and one-third of that group swims regularly for fitness. —Bestreviews, Chicago Tribune, 4 July 2025

Topping off the high-rise will be an upscale rooftop bar and lounge that will be known as the Lurline Cocktail Club, which will showcase 360-degree views of San Diego’s skyline, bay and ocean. —Lori Weisberg, San Diego Union-Tribune, 4 July 2025

Palms, ocean waves and hibiscus flowers were also recurrent motifs popping on cashmere and wool styles — ranging from a coat to a crewneck knit — as well on a lighter wool and silk shirt and pants. —Sandra Salibian, Footwear News, 3 July 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

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