envelope

[ en-vuh-lohp, ahn- ]

noun

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.

envelope

/ ˈɒn-; ˈɛnvəˌləʊp /

noun

1. 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
2. any covering or wrapper
3. biology any enclosing structure, such as a membrane, shell, or skin
4. the bag enclosing the gas in a balloon
5. maths a curve or surface that is tangent to each one of a group of curves or surfaces
6. electronics the sealed glass or metal housing of a valve, electric light, etc
7. telecomm the outer shape of a modulated wave, formed by the peaks of successive cycles of the carrier wave
8. push the envelope informal.
   push the envelope to push the boundaries of what is possible

Word History and Origins

Origin of envelope¹

1700–10; < French enveloppe, derivative of envelopper to envelop

Word History and Origins

Origin of envelope¹

C18: from French enveloppe, from envelopper to wrap around; see envelop ; sense 8 from aeronautics jargon, referring to graphs of aircraft performance

Idioms and Phrases

Idioms

1. push the envelope, to stretch established limits, as in technological advance or social innovation.

Example Sentences

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.

From Fortune

Always follow directions from official sources, like those on your absentee-ballot envelope, over ours.

From FiveThirtyEight

It can only look at the signatures on the envelopes and make sure they appear to be valid.

From Voice of San Diego

Encasing all of this plumbing and the animal cuddled against it lies the big floaty envelope of the outer house.

From Science News

Most importantly, as far as I can tell, there is not a s ingle report of someone dying from licking envelope glue.

From No Straight News

He started out with solo flights, but in this session over the desert outside Dubai he really pushes the envelope.

From The Daily Beast

The parental fold may be about to envelope you—and yet also drive you mad.

From The Daily Beast

On one occasion, Garrison said Williams had him hand one out-of-state doctor an envelope stuffed with $20,000 in cash.

From The Daily Beast

The envelope also contains a warning about the federal penalties for obstructing the mail.

From The Daily Beast

Prince William was seen clutching an envelope, when they left, most likely containing images of the scan.

From The Daily Beast

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.

From Project Gutenberg

Still, if such an envelope should be handed him, he would breathe easier until it was opened.

From Project Gutenberg

Mrs. Haggard, to whom the envelope was addressed, tore it open with some anxiety; her face assumed a pleased expression.

From Project Gutenberg

Desiring him to attend his orders outside, Alphonse broke open the envelope.

From Project Gutenberg

It possessed the greatest interest and attraction for Edna; the envelope, its size and shape, the post-mark, the handwriting.

From Project Gutenberg

Related Words

• bag
• box
• casing
• coat
• container
• jacket
• pocket
• pouch