A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, "the sea" is the interconnected system of Earth's salty, oceanic waters—considered as one global ocean or as several principal oceanic divisions. The sea moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. Although the sea has been traveled and explored since prehistory, the modern scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. The sea is conventionally divided into up to five large oceanic sections—including the International Hydrographic Organization's four named oceans (the Atlantic, Pacific, Indian, and Arctic) and the Southern Ocean; smaller, second-order sections, such as the Mediterranean, are known as seas.
Owing to the present state of continental drift, the Northern Hemisphere is now fairly equally divided between land and sea (a ratio of about 2:3) but the South is overwhelmingly oceanic (1:4.7). Salinity in the open ocean is generally in a narrow band around 3.5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers, or at great depths. About 85% of the solids in the open sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature. Surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun. The direction of all of these is governed by surface and submarine land masses and by the rotation of the Earth (the Coriolis effect).
Former changes in sea levels have left continental shelves, shallow areas in the sea close to land. These nutrient-rich waters teem with life, which provide humans with substantial supplies of food—mainly fish, but also shellfish, mammals, and seaweed—which are both harvested in the wild and farmed. The most diverse areas surround great tropical coral reefs. Whaling in the deep sea was once common but whales' dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Oceanography has established that not all life is restricted to the sunlit surface waters: even under enormous depths and pressures, nutrients streaming from hydrothermal vents support their own unique ecosystem. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earth's atmosphere; both plants and animals first evolved in the sea.
The sea is an essential aspect of human trade, travel, mineral extraction, and power generation. This has also made it essential to warfare and left major cities exposed to earthquakes and volcanoes from nearby faults; powerful tsunami waves; and hurricanes, typhoons, and cyclones produced in the tropics. This importance and duality has affected human culture, from early sea gods to the epic poetry of Homer to the changes induced by the Columbian Exchange, from burial at sea to Basho's haikus to hyperrealist marine art, and inspiring music ranging from the shanties in The Complaynt of Scotland to Rimsky-Korsakov's "The Sea and Sinbad's Ship" to A-mei's "Listen to the Sea". It is the scene of leisure activities including swimming, diving, surfing, and sailing. However, population growth, industrialization, and intensive farming have all contributed to present-day marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a process known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem.
To perceive or detect with the eyes, or as if by sight.
To form a mental picture of.
To witness or observe by personal experience.
"Now I've seen it all!"
"I have been blind since birth and I love to read Braille. When the books arrive in from the library, I can’t wait to see what stories they have sent me."
"I saw military service in Vietnam."
"Do you see what I mean?"
To meet, to visit.
To come to a realization of having been mistaken or misled.
"They're blind to the damage they do, but someday they'll see."
To have an interview with; especially, to make a call upon; to visit.
"to go to see a friend"
To be the setting or time of.
"The 20th century saw humanity's first space exploration."
To ensure that something happens, especially while witnessing it.
"I'll see you hang for this!"
"I saw that they didn't make any more trouble."
To respond to another player's bet with a bet of equal value.
"I'll see your twenty dollars and raise you ten."
To foresee, predict, or prophesy.
"The oracle saw the destruction of the city."
To determine by trial or experiment; to find out (if or whether).
"I'll come over later and see if I can fix your computer."
Used to emphasise a proposition.
"You see, Johnny, your Dad isn't your real dad."
To reference or to study for further details.
"Step 4: In the system, check out the laptop to the student (see: "Logging Resources" in the Tutor Manual)."
"This article is about the insect. For the English rock band, see [https://en.wikipedia.org/wiki/The_Beatles The Beatles]."
"For a complete proof of the Poincaré conjecture, see Appendix C."
Directing the audience to pay attention to the following
"See here, fellas, there's no need for all this rucus!"
Introducing an explanation
"See, in order to win the full prize we would have to come up with a scheme to land a rover on the Moon."
A diocese, archdiocese; a region of a church, generally headed by a bishop, especially an archbishop.
The office of a bishop or archbishop; bishopric or archbishopric
A seat; a site; a place where sovereign power is exercised.
A large body of salt water.
The ocean; the continuous body of salt water covering a majority of the Earth's surface.
A lake, especially if large or if salty or brackish.
"The Caspian Sea, the Sea of Galilee, the Salton Sea, etc."
The swell of the sea; a single wave; billow.
Living or used in or on the sea; of, near, or like the sea.
"Seaman, sea gauge, sea monster, sea horse, sea level, seaworthy, seaport, seaboard, etc."
Anything resembling the vastness of the sea.
A large, dark plain of rock; a mare.
"The Apollo 11 mission landed in the Sea of Tranquility."
A very large lake of liquid hydrocarbon.
perceive with the eyes; discern visually
"Andrew couldn't see out of his left eye"
"in the distance she could see the blue sea"
"I can't see into the future"
be or become aware of something from observation or from a written or other visual source
"I see from your appraisal report that you have asked for training"
be a spectator of (a film, game, or other entertainment); watch
"I went to see King Lear at the Old Vic"
refer to (a specified source) for further information (used as a direction in a text)
"elements are usually classified as metals or non-metals (see chapter 11)"
discern or deduce after reflection or from information; understand
"I can't see any other way to treat it"
"she could see what Rhoda meant"
"I saw that perhaps he was right"
ascertain after inquiring, considering, or discovering an outcome
"I'll go along to the club and see if I can get a game"
regard in a specified way
"he saw himself as a good teacher"
"you and I see things differently"
find good or attractive qualities in (someone)
"I don't know what I see in you"
view or predict as a possibility; envisage
"I can't see him earning any more anywhere else"
used to ascertain or express comprehension, agreement, or continued attention, or to emphasize that an earlier prediction was correct
"see, I told you I'd come"
"it has to be the answer, don't you see?"
experience or witness (an event or situation)
"I shall not live to see it"
"I can't bear to see you so unhappy"
be the time or setting of (something)
"the 1970s saw the beginning of a technological revolution"
meet (someone one knows) socially or by chance
"I saw Colin last night"
visit (a person or place)
"see Alaska in style"
"I went to see Caroline"
meet regularly as a boyfriend or girlfriend
"some guy she was seeing was messing her around"
consult (a specialist or professional)
"you may need to see a solicitor"
give an interview or consultation to
"the doctor will see you now"
escort or conduct (someone) to a specified place
"don't bother seeing me out"
"see that no harm comes to him"
"Lucy saw to it that everyone got enough to eat"
(in poker or brag) equal the bet of (an opponent) and require them to reveal their cards in order to determine who has won the hand.
the place in which a cathedral church stands, identified as the seat of authority of a bishop or archbishop.
A seat; a site; a place where sovereign power is exercised.
The seat of episcopal power; a diocese; the jurisdiction of a bishop; as, the see of New York.
To perceive by the eye; to have knowledge of the existence and apparent qualities of by the organs of sight; to behold; to descry; to view.
To perceive by mental vision; to form an idea or conception of; to note with the mind; to observe; to discern; to distinguish; to understand; to comprehend; to ascertain.
To follow with the eyes, or as with the eyes; to watch; to regard attentively; to look after.
To have an interview with; especially, to make a call upon; to visit; as, to go to see a friend.
To fall in with; to meet or associate with; to have intercourse or communication with; hence, to have knowledge or experience of; as, to see military service.
To accompany in person; to escort; to wait upon; as, to see one home; to see one aboard the cars.
In poker and similar games at cards, to meet (a bet), or to equal the bet of (a player), by staking the same sum.
To have the power of sight, or of perceiving by the proper organs; to possess or employ the sense of vision; as, he sees distinctly.
Figuratively: To have intellectual apprehension; to perceive; to know; to understand; to discern; - often followed by a preposition, as through, or into.
To be attentive; to take care; to give heed; - generally with to; as, to see to the house.
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.
An inland body of water, esp. if large or if salt or brackish; as, the Caspian Sea; the Sea of Aral; sometimes, a small fresh-water lake; as, the Sea of Galilee.
The ocean; the whole body of the salt water which covers a large part of the globe.
The swell of the ocean or other body of water in a high wind; motion or agitation of the water's surface; also, a single wave; a billow; as, there was a high sea after the storm; the vessel shipped a sea.
A great brazen laver in the temple at Jerusalem; - so called from its size.
Fig.: Anything resembling the sea in vastness; as, a sea of glory.
the seat within a bishop's diocese where his cathedral is located
perceive by sight or have the power to perceive by sight;
"You have to be a good observer to see all the details"
"Can you see the bird in that tree?"
"He is blind--he cannot see"
perceive (an idea or situation) mentally;
"Now I see!"
"I just can't see your point"
"Does she realize how important this decision is?"
"I don't understand the idea"
perceive or be contemporaneous with;
"We found Republicans winning the offices"
"You'll see a lot of cheating in this school"
"I want to see results"
"The 1960 saw the rebellion of the younger generation against established traditions"
"I want to see results"
imagine; conceive of; see in one's mind;
"I can't see him on horseback!"
"I can see what will happen"
"I can see a risk in this strategy"
deem to be;
"She views this quite differently from me"
"I consider her to be shallow"
"I don't see the situation quite as negatively as you do"
get to know or become aware of, usually accidentally;
"I learned that she has two grown-up children"
"I see that you have been promoted"
see or watch;
"view a show on television"
"This program will be seen all over the world"
"view an exhibition"
"Catch a show on Broadway"
"see a movie"
find out, learn, or determine with certainty, usually by making an inquiry or other effort;
"I want to see whether she speaks French"
"See whether it works"
"find out if he speaks Russian"
"Check whether the train leaves on time"
"I'll probably see you at the meeting"
"How nice to see you again!"
be careful or certain to do something; make certain of something;
"He verified that the valves were closed"
"See that the curtains are closed"
"control the quality of the product"
go to see for professional or business reasons;
"You should see a lawyer"
"We had to see a psychiatrist"
go to see for a social visit;
"I went to see my friend Mary the other day"
visit a place, as for entertainment;
"We went to see the Eiffel Tower in the morning"
take charge of or deal with;
"Could you see about lunch?"
"I must attend to this matter"
"She took care of this business"
receive as a specified guest;
"the doctor will see you now"
"The minister doesn't see anybody before noon"
date regularly; have a steady relationship with;
"Did you know that she is seeing an older man?"
"He is dating his former wife again!"
see and understand, have a good eye;
"The artist must first learn to see"
deliberate or decide;
"See whether you can come tomorrow"
"let's see--which movie should we see tonight?"
observe as if with an eye;
"The camera saw the burglary and recorded it"
observe, check out, and look over carefully or inspect;
"The customs agent examined the baggage"
"I must see your passport before you can enter the country"
go or live through;
"We had many trials to go through"
"he saw action in Viet Nam"
accompany or escort;
"I'll see you to the door"
match or meet;
"I saw the bet of one of my fellow players"
make sense of; assign a meaning to;
"What message do you see in this letter?"
"How do you interpret his behavior?"
compare (used in texts to point the reader to another location in the text)
a division of an ocean or a large body of salt water partially enclosed by land
anything apparently limitless in quantity or volume
turbulent water with swells of considerable size;
relating to or characteristic of or occurring on the sea or ships;