1. 信封 An envelope is the rectangular paper cover in which you send a letter to someone through the post.
envelope的意思
2. 挑戰限制尺度；突破原有底線(xiàn) If someone pushes the envelope, they do something to a greater degree or in a more extreme way than it has ever been done before.
e.g. There's a valuable place for fashion and design that pushes the envelope a bit... 在原有尺度上有所突破的時(shí)尚和設計受到人們的重視。 e.g. No cinema director had a more profound effect in pushing the envelope of acceptable family entertainment. 在挑戰家庭娛樂(lè )片的接受程度方面，沒(méi)有哪個(gè)電影導演比他的影響更深遠。
envelope英英釋義
envelope
noun
1. any wrapper or covering
2. a flat (usually rectangular) container for a letter, thin package, etc.
3. the bag containing the gas in a balloon
Synonym: gasbag
4. the maximum operating capability of a system (especially an aircraft)
e.g. test pilots try to push the envelope
5. a natural covering (as by a fluid)
e.g. the spacecraft detected an envelope of gas around the comet
6. a curve that is tangent to each of a family of curves