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.
   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

Astronomers refer to this as the common envelope phase, as both stars become wrapped in the same material.

From Science Daily

Among them: the ballot is missing from the envelope, multiple ballots were returned in one envelope, or the voter listed the wrong address.

From Los Angeles Times

Up to 29 days before election day, county elections officials can begin processing and verifying all vote-by-mail ballots to ensure the ballot envelopes are signed and the signatures match the signatures on file.

From Los Angeles Times

Panic buttons and bulletproof glass have been installed at election offices, which are also monitoring mail for envelopes laced with fentanyl.

From Los Angeles Times

They said voters should not lose their right to vote because they made a minor error on the mailing envelope.

From Los Angeles Times

Related Words

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