envelope

1. N-COUNT An envelope is the rectangular paper cover in which you send a letter to someone through the mail. 信封

2. PHRASE 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. 挑戰極限; 突破常槼

There's a valuable place for fashion and design that pushes the envelope a bit. 突破點兒常槼的時尚和設計有其寶貴地位。