envelope
NounOpen English WordNet
Noun (6)envelopes
- a flat (usually rectangular) container for a letter, thin package, etc.Type of containerKinds window envelope
- any wrapper or coveringType of wrapping, wrap
- a curve that is tangent to each of a family of curvesType of curve, curved shapeKinds caustic
- a natural covering (as by a fluid)“the spacecraft detected an envelope of gas around the comet”Type of covering, natural covering
- the maximum operating capability of a system (especially an aircraft)“test pilots try to push the envelope”Type of operating capability, performance capability
- the bag containing the gas in a balloonSynonyms: gasbagType of bagPart of balloon
What does it mean? Question 1 of today’s quiz
Webster's Dictionary (1913)
Origin: F. enveloppe.
1. That which envelops, wraps up, encases, or surrounds; a wrapper; an inclosing cover; esp., the cover or wrapper of a document, as of a letter.
2. Astronomy The nebulous covering of the head or nucleus of a comet; — called also coma.
3. Fortification A work of earth, in the form of a single parapet or of a small rampart. It is sometimes raised in the ditch and sometimes beyond it. Thomas Wilhelm
4. Geometry A curve or surface which is tangent to each member of a system of curves or surfaces, the form and position of the members of the system being allowed to vary according to some continuous law. Thus, any curve is the envelope of its tangents.
4. A set of limits for the performance capabilities of some type of machine, originally used to refer to aircraft; — it is often described graphically as a two-dimensional graph of a function showing the maximum of one performance variable as a function of another. Now it is also used metaphorically to refer to capabilities of any system in general, including human organizations, esp. in the phrase push the envelope. It is used to refer to the maximum performance available at the current state of the technology, and therefore refers to a class of machines in general, not a specific machine.
push the envelope to increase the capability of some type of machine or system; — usually by technological development.
Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54 · with additions: GCIDE editors