a flat paper container, as for a letter or thin package, usually having a gummed flap or other means of closure.
something that envelops; a wrapper, integument, or surrounding cover.
Biology. a surrounding or enclosing structure, as a corolla or an outer membrane.
Geometry. a curve or surface tangent to each member of a set of curves or surfaces.
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.
the fabric structure enclosing the gasbag of an aerostat.
the gasbag itself.
Electronics. the airtight glass or metal housing of a vacuum tube.
the technical limits within which an aircraft or electronic system may be safely operated.
Idioms about envelope
push the envelope, to stretch established limits, as in technological advance or social innovation.
- Also envelop.
- envelop, envelope
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use envelope in a sentence
This uses a harmless virus, usually a retrovirus, that is modified to produce the same external envelope of carbohydrates and proteins as the SARS-CoV-2 virus.Scientists to Wall Street: You don’t really understand how COVID vaccine tests work | Jeremy Kahn | August 24, 2020 | Fortune
Always follow directions from official sources, like those on your absentee-ballot envelope, over ours.Why We’re Planning For An Election Day That Could Last Months | Nathaniel Rakich (firstname.lastname@example.org) | August 14, 2020 | FiveThirtyEight
It can only look at the signatures on the envelopes and make sure they appear to be valid.Politics Report: Down Goes One Hot-Button Ballot Measure | Andrew Keatts | July 18, 2020 | Voice of San Diego
Encasing all of this plumbing and the animal cuddled against it lies the big floaty envelope of the outer house.Larvaceans’ underwater ‘snot palaces’ boast elaborate plumbing | Susan Milius | June 15, 2020 | Science News
Most importantly, as far as I can tell, there is not a s ingle report of someone dying from licking envelope glue.
He started out with solo flights, but in this session over the desert outside Dubai he really pushes the envelope.
The parental fold may be about to envelope you—and yet also drive you mad.
On one occasion, Garrison said Williams had him hand one out-of-state doctor an envelope stuffed with $20,000 in cash.
The envelope also contains a warning about the federal penalties for obstructing the mail.Grimes Campaign “Exploring Legal Options” Against McConnell | Ben Jacobs | October 31, 2014 | THE DAILY BEAST
Prince William was seen clutching an envelope, when they left, most likely containing images of the scan.
Lawrence mingled with the crowd, and as he read he felt a bulky envelope thrust in his hand and caught a glimpse of a dusky arm.The Courier of the Ozarks | Byron A. Dunn
Still, if such an envelope should be handed him, he would breathe easier until it was opened.The Homesteader | Oscar Micheaux
Mrs. Haggard, to whom the envelope was addressed, tore it open with some anxiety; her face assumed a pleased expression.The Pit Town Coronet, Volume I (of 3) | Charles James Wills
Desiring him to attend his orders outside, Alphonse broke open the envelope.
It possessed the greatest interest and attraction for Edna; the envelope, its size and shape, the post-mark, the handwriting.The Awakening and Selected Short Stories | Kate Chopin
British Dictionary definitions for envelope
a flat covering of paper, usually rectangular in shape and with a flap that can be folded over and sealed, used to enclose a letter, etc
any covering or wrapper
biology any enclosing structure, such as a membrane, shell, or skin
the bag enclosing the gas in a balloon
maths a curve or surface that is tangent to each one of a group of curves or surfaces
electronics the sealed glass or metal housing of a valve, electric light, etc
telecomm the outer shape of a modulated wave, formed by the peaks of successive cycles of the carrier wave
push the envelope informal to push the boundaries of what is possible
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012