sea
n.-
1 the ocean (n.) A1 Beginnerthe large body of salt water that covers most of the Earth.
the expanse of salt water that covers most of the Earth's surface and surrounds its landmasses.
ExampleThe children spent the whole afternoon swimming in the sea.
ExampleThe fishing fleet returned to the harbour just as the sea began to turn a deep, stormy grey under the gathering clouds.
UsageOften used with the definite article 'the'.
PitfallWe went to the sea last weekend.We went to the seaside last weekend.Use 'the sea' for the water itself, but use 'the seaside' or 'the coast' when talking about going to a holiday destination by the water.
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2 a large amount (n.) B2 Upper Intermediatea very large number or amount of something that looks like it has no end.
a vast or overwhelming quantity of something, used figuratively to suggest immense scale or movement.
ExampleLooking out from the stage, the singer saw a sea of happy faces.
ExampleThe protesters formed a sea of umbrellas in the square, shielding themselves from the relentless autumn rain while they waited for the announcement.
UsageUsually follows the pattern 'a sea of [noun]'.
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3 rough water or waves (n.) B2 Upper Intermediatethe movement of the water, especially when it is rough or has big waves.
the state of the water's surface in terms of waves and swell, often used in the plural to describe rough conditions.
ExampleThe small boat struggled to stay upright in the heavy seas.
ExampleThe captain decided to change course to avoid the high seas reported by the weather station further north.
UsageOften used in the plural ('heavy seas') to describe weather conditions.
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4 lunar plain (n.) C2 Proficiency Technical Sciencea large, dark, flat area on the surface of the moon.
a large, dark basaltic plain on Earth's Moon, historically mistaken for a body of water.
ExampleThe Sea of Tranquility is the most famous dark plain on the moon.
ExampleEarly astronomers named these vast basaltic plains 'seas' under the mistaken belief that they were filled with water rather than volcanic rock.
UsageOften translated from the Latin 'mare'.
Teacher's tipThis is a specialized term used in astronomy; students will mostly encounter it in textbooks about space.
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5 particle physics (n.) C2 Proficiency Technical Sciencea group of particles that constantly appear and disappear inside an atom.
a theoretical model of the vacuum or the interior of a hadron consisting of a constant flux of virtual particles.
ExampleScientists study the sea of quarks to understand how atoms work.
ExampleThe distribution of momentum among the sea quarks provides crucial data for high-energy collision experiments in particle accelerators.
UsageUsed specifically in quantum field theory and particle physics.
- quark sea
Inherited from Middle English see, from Old English sǣ, from Proto-West Germanic saiwi (“body of water”), from Proto-Germanic saiwiz, itself either: Derived from Proto-Indo-European sh₂ey-wo- (“to be fierce, afflict”). Related to Latin saevus (“wild, fierce”), Tocharian B saiwe (“itch”), and Latvian sievs, sīvs (“sharp, biting”). More at sore. Derived from Proto-Germanic sīhwaną (“to percolate, filter”), from Proto-Indo-European *seykʷ-. Cognates Cognate with Yola zea, zee (“sea”), North Frisian See, sia, siie (“sea; lake”), Saterland Frisian See, Säi (“sea”), West Frisian see (“sea”), Cimbrian, Mòcheno sea (“lake”), Dutch zee (“sea”), German, German Low German See (“sea”), Limburgish Sië, zieë (“sea, ocean; lake”), Luxembourgish Séi (“lake”), West Flemish zji (“sea; seaside”), Danish sø (“sea; lake”), Faroese sjógvur (“sea; big wave”), Icelandic sjár, sjór, sær (“sea”), Norwegian Bokmål, Norwegian Nynorsk sjø (“sea, ocean; lake”), Swedish sjö (“sea; lake; big wave”), Gothic 𐍃𐌰𐌹𐍅𐍃 (saiws, “lake, sea; marshland”).