[en-vuh-lohp, ahn-] 
| 1. | a flat paper container, as for a letter or thin package, usually having a gummed flap or other means of closure. |
| 2. | something that envelops; a wrapper, integument, or surrounding cover. |
| 3. | Biology. a surrounding or enclosing structure, as a corolla or an outer membrane. |
| 4. | Geometry. a curve or surface tangent to each member of a set of curves or surfaces. |
| 5. | Radio. (of a modulated carrier wave) a curve connecting the peaks of a graph of the instantaneous value of the electric or magnetic component of the carrier wave as a function of time. |
| 6. | the fabric structure enclosing the gasbag of an aerostat. |
| 7. | the gasbag itself. |
| 8. | Electronics. the airtight glass or metal housing of a vacuum tube. |
| 9. | the technical limits within which an aircraft or electronic system may be safely operated. |
| 10. | push the envelope, to stretch established limits, as in technological advance or social innovation. |
| en·ve·lope (ěn'və-lōp', ŏn'-) n.
[French enveloppe, from envelopper, to envelop, from Old French envoloper; see envelop.] Usage Note: The word envelope was borrowed into English from French during the early 18th century, and the first syllable acquired the pronunciation (ŏn) as an approximation to the nasalized French pronunciation. Gradually the word has become anglicized further and is now most commonly pronounced (ěn'və-lōp'). The earlier pronunciation is still considered acceptable, however. A recent survey reveals that the (ŏn'-) pronunciation for the word envelope is used by 30 percent of the Usage Panel and is recognized as an acceptable variant by about 20 percent of those Panelists who normally use the (ěn'-) pronunciation. Other similar words borrowed from French in the modern period include envoy (17th century), encore, ennui, ensemble, entree (18th century), entourage, and entrepreneur (19th century). Most retain their pseudo-French pronunciations, with the exception of envoy, which, like envelope, is mainly pronounced with (ěn) now. |
Envelope
A trading band composed of two moving averages, one of which is shifting upwards and the other shifting downwards.
Investopedia Commentary
These trading bands are used by technical analysts to define a stock's upper and lower boundaries. Signals to sell occur when the stock price reaches the upper band, and buy signals are generated when the price reaches the lower band.
The reasoning behind the sell and buy signals is that stock prices tend to bounce off the bands. Even though buyers and sellers will temporarily pressure a stock's price to its extremes, it should re-stabilize to more realistic levels found within the envelope.
See also: Bollinger Bands, Chartist, Consolidation, Gann Angles, Moving Average, Technical Analysis
envelope en·ve·lope (ěn'və-lōp', ŏn'-)
n.
An enclosing structure or cover, such as a membrane or the outer coat of a virus.
vəˌloʊp