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

Nearby words

  1. se,
  2. se defendendo,
  3. se tenant,
  4. se-,
  5. se-tenant,
  6. sea anchor,
  7. sea anemone,
  8. sea aster,
  9. sea bag,
  10. sea bass


Origin of sea

before 900; Middle English see, Old English sǣ; cognate with Dutch zee, German See, Old Norse sær sea, Gothic saiws marsh Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for at sea



  1. the seathe mass of salt water on the earth's surface as differentiated from the landRelated adjectives: marine, maritime, thalassic
  2. (as modifier)sea air
(capital when part of place name)
  1. one of the smaller areas of oceanthe Irish Sea
  2. a large inland area of waterthe Caspian Sea
turbulence or swell, esp of considerable sizeheavy seas
(capital when part of a name) astronomy any of many huge dry plains on the surface of the moonSee also mare 2
anything resembling the sea in size or apparent limitlessness
the life or career of a sailor (esp in the phrase follow the sea)
at sea
  1. on the ocean
  2. in a state of confusion
go to sea to become a sailor
put to sea or put out to sea to embark on a sea voyage

Word Origin for sea

Old English sǣ; related to Old Norse sǣr, Old Frisian sē, Gothic saiws, Old High German sēo

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for at sea


Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for at sea



The continuous body of salt water that covers most of the Earth's surface.
A region of water within an ocean and partly enclosed by land, such as the North Sea. See Note at ocean.
A large body of either fresh or salt water that is completely enclosed by land, such as the Caspian Sea.
Astronomy A mare.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with at sea

at sea


Aboard a ship, on the ocean, as in Within a few hours the ship would be out at sea. During World War II a famous American newscaster addressed his radio broadcasts to listeners everywhere, including “all the ships at sea.” [1300s]


Also, all at sea. Perplexed, bewildered, as in She was all at sea in these new surroundings. This idiom transfers the condition of a vessel that has lost its bearings to the human mind. Charles Dickens used it in Little Dorrit (1855): “Mrs. Tickit ... was so plainly at sea on this part of the case.” [Second half of 1700s]


In addition to the idiom beginning with sea

  • sea legs
  • seal of approval
  • seal off
  • seal one's fate

also see:

  • 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)
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.