noun (n)

• a division of an ocean or a large body of salt water partially enclosed by land(noun.object)

  source: wordnet30
• anything apparently limitless in quantity or volume(noun.quantity)

  Synonym:
  ocean
  

  source: wordnet30
• turbulent water with swells of considerable size(noun.phenomenon)

  Example:
  Heavy seas.
  

  source: wordnet30
• One of the larger bodies of salt water, less than an ocean, found on the earth's surface; a body of salt water of second rank, generally forming part of, or connecting with, an ocean or a larger sea; as, the Mediterranean Sea; the Sea of Marmora; the North Sea; the Carribean Sea.(noun)

  source: webster1913