Envelope
WordNet
noun
(1) Any wrapper or covering
(2) A flat rectangular paper container for papers
(3) The bag containing the gas in a balloon
(4) The maximum operating capability of a system
"Test pilots try to push the envelope"
(5) A natural covering (as by a fluid)
"The spacecraft detected an envelope of gas around the comet"
(6) A curve that is tangent to each of a family of curves
WiktionaryText
Noun
envelope
- A paper or cardboard wrapper used to enclose and small, flat items, especially letters, for mailing.
- Something that envelops; a wrapping
- A bag containing the lifting gas of a balloon or airship; fabric that encloses the gas-bags of an airship
- A mathematical curve, surface, or higher-dimensional object that is the tangent to a given family of lines, curves, surfaces, or higher-dimensional objects.
- A curve that bounds another curve or set of curves, as the modulation envelope of an amplitude-modulated carrier wave in electronics.
- The shape of a sound, which may be controlled by a synthesizer or sampler.
- The information used for routing an email that is transmitted with the email but not part of its contents.
- An enclosing structure or cover, such as a membrane.
- The set of limitations within which a technological system can perform safely and effectively.