sea

American  

[see] / si /

noun

1. the salt waters that cover the greater part of the earth's surface.

2. a division of these waters, of considerable extent, more or less definitely marked off by land boundaries.

   the North Sea.

3. one of the seven seas; ocean.

4. a large lake or landlocked body of water.

5. the degree or amount of turbulence of the ocean or other body of water, as caused by the wind.

6. the waves.

7. a large wave.

   The heavy seas almost drowned us.

8. a widely extended, copious, or overwhelming quantity.

   a sea of faces; a sea of troubles.

   Synonyms:

   mass, abundance, host, multitude

9. the work, travel, and shipboard life of a sailor.

   The sea is a hard life but a rewarding one.

10. Astronomy. mare.

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adjective

1. of, relating to, or adapted for use at sea.

idioms

1. at sea, Also

   1. on the ocean.

   2. perplexed; uncertain.

      completely at sea as to how to answer the question.

2. go to sea,

   1. to set out on a voyage.

   2. to embark on a nautical career.

3. half seas over, partly or completely drunk: Also

   They came home at dawn, looking half seas over.

4. put to sea, to embark on a sea voyage: Also put out to sea.

   The expedition is nearly ready to put to sea.

5. follow the sea, to pursue a nautical career.

   Many boys then dreamed of following the sea.

sea British  

/ siː /

noun

1. 1. the mass of salt water on the earth's surface as differentiated from the land

   2. ( as modifier )

      sea air

2. (capital when part of place name)

   1. one of the smaller areas of ocean

      the Irish Sea

   2. a large inland area of water

      the Caspian Sea

3. turbulence or swell, esp of considerable size

   heavy seas

4. (capital when part of a name) astronomy any of many huge dry plains on the surface of the moon See also mare 2

5. anything resembling the sea in size or apparent limitlessness

6. the life or career of a sailor (esp in the phrase follow the sea )

7. 1. on the ocean

   2. in a state of confusion

8. to become a sailor

9. to embark on a sea voyage

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sea Scientific  

/ sē /

1. The continuous body of salt water that covers most of the Earth's surface.

2. A region of water within an ocean and partly enclosed by land, such as the North Sea.

3. See Note at ocean

4. A large body of either fresh or salt water that is completely enclosed by land, such as the Caspian Sea.

5. Astronomy A mare.

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sea More Idioms  

More idioms and phrases containing sea

• at sea
• between a rock and a hard place (devil and the deep blue sea)
• high seas
• not the only fish in the sea
• put out (to sea)

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Etymology

Origin of sea

First recorded before 900; Middle English see, Old English sǣ; cognate with Dutch zee, German See, Old Norse sær “sea,” Gothic saiws “marsh”

Example Sentences

It is now recognized as the earliest known chelicerate, a group that includes spiders, scorpions, horseshoe crabs, and sea spiders.

From Science Daily • Apr. 3, 2026

To the right, with the Iranian coast only 40 miles away, the dark-blue sea is completely empty.

From The Wall Street Journal • Apr. 3, 2026

The proposals for a site on Loch Ailort, a sea loch west of Fort William, had received more than 65 objections.

From BBC • Apr. 1, 2026

Swap out the poppy seeds for chia seeds and add sesame seeds, onion flakes, garlic powder and flaky sea salt to make an omega-3-rich rendition of the popular Everything Bagel Seasoning.

From Salon • Mar. 31, 2026

Barrel after barrel was being rolled across the deck to be maimed and tossed into the sea.

From "Glitch" by Laura Martin

Related Words

• expanse
• lake
• ocean
• pond
• surf