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