- (often the sea)[uncountable](also literary seas [plural])(especially British English)
the salt water that covers most of the earth’s surface and surrounds its continents and islands 海；海洋 
The waste was dumped in the sea. 废物倒入海中。 The wreck is lying at the bottom of the sea. 沉船躺在海底。 - by sea
to travel by sea 海上旅行 - by the sea
a cottage by the sea 海滨小屋 He was shot down into the sea off (= near) Japan. 他在日本附近被击落入海。 We left port and headed for the open sea (= far away from land). 我们离开港口，向外海驶去。 the cold seas of the Arctic 北极地区寒冷的海洋 a sea voyage 海上航行 a hotel room with sea view 旅馆海景房 The temperature of most of the deep sea is only just above freezing. 大多数深海的温度仅略高于冰点。 The boat, broken to bits, lay on the sea floor. 那艘破成碎片的船躺在海底。 The amount of Arctic sea ice in summer has shrunk 15 to 20%. 夏季北极海冰的数量减少了15%至20%。
British/American sea / oceansea / ocean- In British English, the usual word for the mass of salt water that covers most of the earth’s surface is the sea. In North American English, the usual word is the ocean:
A swimmer drowned in the sea/ocean this morning. 今天早上一名游泳者在海里淹死了。
- The names of particular areas of seas, however, are fixed:
然而，特定的海洋名称用 sea 或 ocean 是固定的： the Mediterranean Sea 地中海 the Atlantic Ocean 大西洋
- Sea/ocean are also used if you go to the coast on holiday:
We’re spending a week by the sea/at the ocean in June 我们六月份要在海滨度假一个星期。
We’re going to the beach for vacation. 我们要去海滨度假。
Homophones seas | sees | seizeseas sees seizesee also deep-sea, high seas, oceanExtra ExamplesTopics Transport by watera1, Holidaysa1, Geographya1I love swimming in the sea! 我喜欢在海里游泳！ We'll go down to the sea for a swim before dinner. 晚饭前，我们会去海边游泳。 three ships sailing on the sea 三艘在海上航行的船 In recent years the sea has risen by a couple of inches. 近些年，海面上升了几英寸。 The sea has receded since the river was diverted. 河流改道以后，海水退后了。 They live by the sea. 他们住在海边。 a house overlooking the sea 一处俯临大海的房子 Thousands of Haitians tried to cross the sea to Florida. 数千名海地人试图横渡大海前往佛罗里达。 We sent our furniture by sea. 我们的家具是经由海路运输的。
Oxford Collocations Dictionaryadjective- calm
- choppy
- heavy
- …
- cross
- roam
- sail
- …
- rise
- recede
- water
- bed
- bottom
- …
- at sea
- across the sea
- by sea
- …
- the bottom of the sea
- the depths of the sea
- the edge of the sea
- …
- [countable]
(often Sea, especially as part of a name 常作 Sea，尤作名称的一部分 a large area of salt water that is part of an ocean or surrounded by land 海 the North Sea 北海 the Caspian Sea 里海
Extra ExamplesTopics Geographya1We crossed the Mediterranean Sea on a cruise ship. 我们乘坐旅游客轮穿越地中海。 We sailed across the Black Sea in a yacht. 我们乘坐游艇横渡黑海。 They sailed the seven seas in search of adventure. 他们航遍了世界所有海洋，寻求冒险刺激。
- [countable] (also seas [plural])
the movement of the waves of the sea 海面情况；海浪状况 It was a calm sea. 海上风平浪静。 The sea was very rough. 海上风急浪高。 The ship sank in heavy seas. 船在汹涌的大海中沉没了。 stormy/choppy seas 暴风雨/波涛汹涌的大海
Extra ExamplesTopics Geographya1A boy drowned last night after being swept into rough seas by a large wave. 昨晚一男孩被巨浪卷入汹涌的大海溺水而死。 The sea was too rough for sailing in small boats. 海上风浪太大，小船不能航行。
Oxford Collocations Dictionaryadjective- calm
- choppy
- heavy
- …
- cross
- roam
- sail
- …
- rise
- recede
- water
- bed
- bottom
- …
- at sea
- across the sea
- by sea
- …
- the bottom of the sea
- the depths of the sea
- the edge of the sea
- …
- [singular] sea of something
a large amount of something that stretches over a wide area 大量；茫茫一片 Extra ExamplesThe taxi made its way through a sea of bicycles. 出租车在自行车的海洋中穿行。 The plane passed over a sea of greenery. 飞机飞过一片绿色的海洋。 They were surrounded by a sea of boxes. 他们被淹没在盒子的海洋里。
Oxford Collocations Dictionaryadjective- endless
- vast
- be surrounded by
- sea of
Word OriginOld English sǣ, of Germanic origin; related to Dutch zee and German See.
Idioms
at sea
on the sea, especially in a ship, or in the sea 在海上（尤指乘船）；在海里 Extra ExamplesTopics Transport by waterb1Her husband was in the navy and spent a lot of time away at sea. 她丈夫过去是海军，经常在海上航行。 We spent three weeks at sea. 我们在海上航行了 3 个星期。
confused and not knowing what to do 困惑；茫然；不知所措
between the devil and the deep blue sea
in a difficult situation where there are two equally unpleasant or unacceptable choices 进退维谷；左右为难
go/run away to sea
to become a sailor; to leave your home and family without permission to become a sailor 去当水手；当海员 He ran away to sea at the age of 13. 他13岁时逃到了海上。
out to sea
far away from land where the sea is deepest 向（或在）外海 She fell overboard and was swept out to sea. 她从船上落入水中，被海浪冲向外海。 She stood on the cliff, staring out to sea. 她站在悬崖上，凝望着大海。
put (out) to sea
to leave a port or harbour by ship or boat 起航；出海 The ship put to sea in deteriorating weather conditions. 船在不断恶化的天气条件下离岸起航。
there are plenty more fish in the sea
used to comfort somebody whose romantic relationship has ended by saying that there are many other people with whom they may have a successful relationship in the future 海里的鱼有的是；还有很多一样好的（人或事物）