Noun
-
the bag containing the gas in a balloon
-
the maximum operating capability of a system (especially an aircraft)
"test pilots try to push the envelope"
-
a natural covering (as by a fluid)
"the spacecraft detected an envelope of gas around the comet"
-
a curve that is tangent to each of a family of curves
-
any wrapper or covering
-
a flat (usually rectangular) container for a letter, thin package, etc.