sea
sea — noun
1. the salty liquid found in the planet's deepest basins, between the land masses,
the salty liquid found in the planet's deepest basins, between the land masses, or a named stretch of this water partly enclosed by land and not as big as an ocean
The children spent every afternoon swimming in the warm sea during their holiday in Greece.
the + sea for a specific body of water
The Mediterranean Sea connects Europe to Africa and is a major shipping route.
proper name + Sea for a named sea
From the cliff, Yara watched the sea stretch all the way to the horizon.
The sea was so calm that the fishing boats hardly moved on the surface.
文法句型
the + sea
[proper name] + Sea
a/the + sea of + noun
用法筆記
Can be uncountable ('the sea is blue') or countable with a proper name ('the Black Sea'). When referring generally to the world's salt water, use 'the sea' without a capital letter. Named seas take the definite article and capital letters.
常見錯誤
2. a very large number or amount of people or things that fills an area and is diff
a very large number or amount of people or things that fills an area and is difficult to see the end of, like a wide stretch of water
The singer walked on stage and saw a sea of waving hands and bright lights.
a sea of + plural noun for large number
After the storm, a sea of fallen leaves covered every path in the park.
The charity event created a sea of colourful banners and flags across the entire square.
Putri opened her inbox to find a sea of unread messages waiting for her.
文法句型
a sea of + plural noun
用法筆記
Almost always used in the fixed phrase 'a sea of + [plural noun]'. The noun that follows is typically countable and describes visible items or people. This is a figurative extension of the literal meaning.
常見錯誤
3. the open ocean, especially as the destination or setting of a ship's journey aft
the open ocean, especially as the destination or setting of a ship's journey after leaving port, or the state of travelling on a ship away from land
The captain ordered the crew to put to sea as soon as the storm passed.
put to sea: leave port by ship
Nikos spent six months at sea on a cargo ship travelling between Asian ports.
at sea: on a voyage away from land
After the engine failed, the fishing boat was lost at sea for three days.
Esteban had never been to sea before, so the first wave made him feel sick.
- voyage
a noun for the journey itself, not the location
- open water
describes the sea away from the coast, used in both literal and technical contexts
文法句型
at sea
put to sea
go to sea
be lost at sea
用法筆記
This meaning appears almost exclusively in fixed prepositional phrases. 'At sea' describes being on a voyage; 'put to sea' describes the act of leaving port; 'go to sea' describes starting a career or voyage as a sailor. The literal noun 'sea' in these phrases refers to the open ocean as a space for travel.
常見錯誤
4. any of the dark, level patches found on the lunar surface which early observers
any of the dark, level patches found on the lunar surface which early observers wrongly believed to be oceans but are in fact dry volcanic plains
The Apollo 11 crew landed near the edge of the Sea of Tranquillity on the moon.
proper name: Sea of + Latin name
Through his telescope, Felix saw the dark shapes called seas on the moon.
The moon's seas are ancient lava plains, not actual bodies of water.
The largest sea on the moon, Oceanus Procellarum, covers four million square kilometres.
- mare
the Latin term used in astronomy; plural is 'maria'
- lunar plain
a more scientifically accurate description than 'sea'
- highland
the lighter, higher areas on the moon's surface, called 'terrae'
文法句型
the Sea of + [Latin name]
the + [Latin name] + Sea
用法筆記
Used only in technical astronomical contexts, almost always with a Latin proper name like 'Mare Tranquillitatis' or its English translation 'Sea of Tranquillity'. The singular Latin term is 'mare' and the plural is 'maria'.
常見錯誤
5. the condition of the surface of an ocean or lake in terms of wave size and movem
the condition of the surface of an ocean or lake in terms of wave size and movement, especially when waves are large and dangerous
The weather forecast warned of rough seas and strong winds along the entire coast.
rough seas: large, dangerous waves
A heavy sea swept across the deck and soaked the crew.
heavy sea: large, powerful wave(s)
The captain checked the sea conditions before deciding whether to leave the harbour that evening.
Small boats were told to stay in port because the seas were dangerously high.
- calm
the absence of large waves or rough movement
文法句型
rough/heavy/calm + sea(s)
sea conditions
用法筆記
In this sense 'sea' is often used in the plural ('the seas are rough') or with descriptive adjectives ('a heavy sea', 'a calm sea'). 'Rough sea' and 'heavy sea' are fixed collocations used in weather reports and maritime communication.