a part of a piece of clothing that covers all or part of your arm 袖子 
Extra ExamplesTopics Clothes and Fashionb2I looked around to see who was tugging at my sleeve. 我四下张望，想知道是谁在拽我的袖子。 It was sunny, and everyone was in short sleeves. 阳光明媚，人人都穿着短袖。 There's tomato on your sleeve. 你袖子上沾上番茄了。
Oxford Collocations Dictionaryadjective- long
- short
- left
- …
- push back
- push up
- roll up
- …
- in… sleeves
- on a/the sleeve
- -sleeved
(in adjectives 构成形容词 having sleeves of the type mentioned 有…袖子的 a short-sleeved shirt 短袖衬衫
- (also jacket especially in North American English)
a stiff paper cover for a record 唱片套 a colourful sleeve design 色彩斑斓的唱片套设计 He designed record sleeves for the Rolling Stones. 他为滚石乐队设计唱片套。
Oxford Collocations Dictionaryadjective- album
- CD
- DVD
- …
- design
- notes
- design
a tube that covers a part of a machine to protect it （机器的）套筒，套管
Word OriginOld English slēfe, slīef(e), slȳf; related to Middle Dutch sloove ‘covering’.
Idioms
an ace up your sleeve (British English)
(North American English an ace in the hole)
- (informal)
a secret advantage, for example a piece of information or a skill, that you are ready to use if you need to 秘藏的王牌；撒手锏；锦囊妙计
have a card up your sleeve
to have an idea, a plan, etc. that will give you an advantage in a particular situation and that you keep secret until it is needed 有锦囊妙计；留有一招
have a trick, some more tricks, etc. up your sleeve
to have an idea, some plans, etc. that you keep ready to use if it becomes necessary 袖藏玄机；胸有成竹；自有锦囊妙计 I have a few tricks up my sleeve. 我自有锦囊妙计。
have/keep something up your sleeve
to keep a plan or an idea secret until you need to use it 有锦囊妙计；胸中自有主张 Actually I do have a few ideas up my sleeve. 事实上我确实有一些想法。
laugh up your sleeve (at somebody/something)
- (informal)
to secretly think that something is funny 暗自发笑；窃笑
roll up your sleeves
to prepare to work or fight 捋起袖子；准备动手；摩拳擦掌
wear your heart on your sleeve
to allow your feelings to be seen by other people 让感情外露；把心事挂在脸上 He’s not one to wear his heart on his sleeve. 他不是那种把心放在袖子上的人。