en·ve·lope
noun/ˈenvələʊp/, /ˈɒnvələʊp/
/ˈenvələʊp/, /ˈɑːnvələʊp/
Idioms 
enlarge imagea flat paper container used for sending letters in, with a part that you stick down to close it信封 - Writing paper and envelopes are provided in your room.
您的房间内提供信纸和信封。 - a padded/prepaid envelope
有衬垫／预付邮资的信封
Extra Examples- He gave her the envelope of certificates.
他给她证书的封套。 - He quickly stuffed the money back into the envelope.
他迅速把钱塞回信封里。 - I couldn't read the address on the envelope.
我看不清楚信封上的地址。 - I had put the letter in the wrong envelope.
我把信放错了信封。 - I scribbled his phone number on the back of an envelope.
我在一个信封的背面草草记下了他的电话号码。 - Please enclose a self-addressed envelope if you would like a reply.
想要收到回复者，请附寄一个带回信地址的信封。 - a self-addressed stamped envelope
一个贴足邮票并写明回邮地址的信封 - The envelope was marked ‘Personal’.
信封上标有“私人信件”字样。 - The letter was suspicious, and I considered steaming open the envelope.
这封信有点儿可疑，我认为应该用蒸汽拆封。 - To apply, use the enclosed reply-paid envelope (no stamp needed).
申请可用随附的已付费信封。 - You don't earn much stuffing envelopes.
将信封里塞得满满的不会给你带来多大的好处。 - an envelope addressed in my mother's round handwriting
用我母亲的圆体字迹书写地址的信封 - an official-looking manila envelope
一个看起来很正式的马尼拉纸信封
Oxford Collocations Dictionaryadjective- bulky
- fat
- thick
- …
- open
- rip open
- slit open
- …
- contain something
- enclose something
- in an/the envelope
- into an/the envelope
- on an/the envelope
- …
- the back of an envelope
- Writing paper and envelopes are provided in your room.
- a flat container made of plastic for keeping papers in
塑料封套；塑料封皮 - Each item was tagged and sealed in a plastic envelope.
每件物品都贴了标签，封进了塑料封套。
- Each item was tagged and sealed in a plastic envelope.
Word Originmid 16th cent. (in the sense ‘wrapper, enveloping layer’; originally as envelope): from French enveloppe, from envelopper ‘envelop’. The sense ‘covering of a letter’ dates from the early 18th cent.
Idioms
(on the) back of an envelope
- used to talk about planning or calculating something in a way that is not detailed, exact or complete
未经慎密思考的 - We added up our savings on the back of an envelope.
我们把我们的积蓄写在信封背面。 - back-of-the-envelope calculations
粗略计算
- We added up our savings on the back of an envelope.
push the envelope
- (informal) to go beyond the limits of what is allowed or thought to be possible
超越界线；突破 - He is a performer who consistently pushes the envelope of TV comedy.
他是一个在电视喜剧表演中不断寻求突破的演员。
- He is a performer who consistently pushes the envelope of TV comedy.