en·ve·lope
Pronounced:
/ˈɛnvəˌloʊp, ˈɑ:nvəˌloʊp/
Function:
nounInflected forms:
plural en·ve·lopesMeaning:
[count] : an enclosing cover for a letter, card, etc. —see picture at mail
push the envelope
: to go beyond the usual or normal limits by doing something new, dangerous, etc. ▪ a director who has pushed the envelope in his recent films ▪ a new airplane design that pushes the envelope

