Collins COBUILD Advanced Learner’s Dictionary

un|der ◆◆◆ /ʌ ndə ^r / In addition to the uses shown below, under is also used in phrasal verbs such as 'go under' and 'knuckle under'. 1 PREP If a person or thing is under something, they are at a lower level than that thing, and may be covered or hidden by it. □  …swimming in the pool or lying under an umbrella. □  Under a wide shelf that holds coffee jars stands a pile of magazines. □  She buried her head under the covers, pretending to be asleep. □  A path runs under the trees.

2 PREP In a place such as a sea, river, or swimming pool, if someone or something is under the water, they are fully in the water and covered by it. □  They said he'd been held under the water and drowned. □  Goldfish were swimming lazily in a group just under the surface. ● ADV [ADV after v] Under is also an adverb. □  When the water was up to his neck, a hand came from behind and pushed his head under.

3 PREP If you go under something, you move from one side to the other of something that is at a higher level than you. □  He went under a brick arch. □  A river boat passed under the bridge.

4 PREP Something that is under a layer of something, especially clothing, is covered by that layer. □  I was wearing two sweaters under the green army jacket. □  It was hard to see the colours under the layer of dust.

5 PREP You can use under before a noun to indicate that a person or thing is being affected by something or is going through a particular process. □  …fishermen whose livelihoods are under threat. □  I'm rarely under pressure and my co-workers are always nice to me. □  Firefighters said they had the blaze under control. □  He was rushed to court yesterday under armed guard.

6 PREP If something happens under particular circumstances or conditions, it happens when those circumstances or conditions exist. □  His best friend was killed by police under extremely questionable circumstances. □  Under normal conditions, only about 20 to 40 per cent of vitamin E is absorbed.

7 PREP If something happens under a law, agreement, or system, it happens because that law, agreement, or system says that it should happen. □  Under law, your employer has the right to hire a temporary worker to replace you. □  Under the Constitution, you cannot be tried twice for the same crime.

8 PREP If something happens under a particular person or government, it happens when that person or government is in power. □  There would be no new taxes under his leadership. □  …the realities of life under a brutal dictatorship.

9 PREP If you study or work under a particular person, that person teaches you or tells you what to do. □  Kiefer was just one of the artists who had studied under Beuys in the early Sixties. □  I am the new manager and you will be working under me.

10 PREP If you do something under a particular name, you use that name instead of your real name. □  Were any of your books published under the name Amanda Fairchild? □  The patient was registered under a false name.

11 PREP You use under to say which section of a list, book, or system something is in. □  This study is described under 'General Diseases of the Eye'. □  'Where would it be?'—'Filed under C, second drawer down.'