/ˈʌndə(r) ||; ˈʌndɚ/prep adv1 in or to a position that is below sth 在…下面；到…之下: We found him hiding under the table. 我们发现他藏在桌子底下。The dog crawled under the gate and ran into the road. 狗从大门底下爬出去，跑到路上去了。
Compare under, below, beneath and underneath. You use under to say that one thing is directly under another thing. There may be a space between the two things The cat is asleep under the table or one thing may be touching or covered by the other thing I think your letter is under that book. You can use below to say that one thing is in a lower position than another thing They live on the floor below us. The skirt comes down to just below the knee. You use under (not below) to talk about movement from one side of something to the other side We swam under the bridge. You can use beneath in formal writing to say that one thing is directly under another thing, but under is more common. You can use underneath in place of under when you want to emphasize that something is being covered or hidden by another thing Have you looked underneath the sofa as well as behind it? 比较under、below、beneath及underneath。under指一物直接在另一物之下，两者之间可能有空隙：The cat is asleep under the table.猫在桌子下面睡着了。或一物与另一物接触着或为其所覆盖着：I think your letter is under that book. 我想你的信就在那本书下面。形容一物处于比另一物较低的位置可用below：They live on the floor below us.他们住在我们底下一层。·The skirt comes down to just below the knee.裙子刚好长到膝盖下面。指由某物的一边移动到另一边用under（不用below）﹕We swam under the bridge.我们从桥下游过。在正式书面语中，指一物直接在另一物之下可以用beneath，但under较常用；用underneath，不用under，以强调一物覆盖或遮住另一物：Have you looked underneath the sofa as well as behind it?你在沙发下面和后面找过没有？ 2 below the surface of sth; covered by sth 在…表面之下；被覆盖: Most of an iceberg is under the water. 冰山的大部份都在水下。He was wearing a vest under his shirt. 他衬衫下面穿着背心。
3 less than a certain number; younger than a certain age 少于；…岁以下: People working under 20 hours a week will pay no extra tax. 每周工作少于20小时的人不用缴额外税款。Nobody under eighteen is allowed to buy alcohol. 十八岁以下的人不准买酒。
4 governed or controlled by sb/sth 受…统治或控制: The country is now under martial law. 该国现在实施军事管制。
5 according to a law, agreement, system, etc 根据（法律、协议、制度等）: Under English law you are innocent until you are proved guilty. 根据英国法律，任何人除非被证明有罪，否则都是无罪。
6 experiencing a particular feeling, process or effect 经历（某种感受或过程）；在（某事）影响下: He was jailed for driving under the influence of alcohol. 他因酒后驾车而被关进监牢。a building under construction 建筑中的大厦The manager is under pressure to resign. 经理被迫辞职。I was under the impression that Bill was not very happy there. 我觉得比尔在那里不太称心。
7 using a particular name 用某名称: to travel under a false name 用假名旅行
8 found in a particular part of a book, list, etc 在（书、名单等的）某部份: You'll find some information on rugby under ‘team sports’. 在“团队运动”那部份可以找到有关橄榄球的数据。