Envelope (Noun)
Meaning 1
A curve that is tangent to each of a family of curves.
Classification
Nouns denoting two and three dimensional shapes.
Hypernyms
Meaning 2
A natural covering (as by a fluid); "the spacecraft detected an envelope of gas around the comet".
Classification
Nouns denoting natural objects (not man-made).
Hypernyms
Meaning 3
The maximum operating capability of a system (especially an aircraft); "test pilots try to push the envelope".
Classification
Nouns denoting attributes of people and objects.
Hypernyms
Meaning 4
The bag containing the gas in a balloon.
Classification
Nouns denoting man-made objects.
Synonyms
Meaning 5
A flat (usually rectangular) container for a letter, thin package, etc..
Classification
Nouns denoting man-made objects.