envelope

American  

[en-vuh-lohp, ahn-] / ˈɛn vəˌloʊp, ˈɑn- /

noun

• envelopes
  plural

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.

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idioms

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

envelope British  

/ 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. informal to push the boundaries of what is possible

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Other Word Forms

Noun Inflected Forms

• envelopes
  plural

Etymology

Origin of envelope

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

Explanation

An envelope is something that envelops, or wraps around. It usually refers to the thing you stick a stamp on and snail mail. In the early 1700s, envelope, the noun for "wrapper," evolved from the French enveloppe, meaning “to envelop.” Envelope is always a noun, unlike the verb envelop which means “to wrap, cloak.” Synonyms for envelope range from casing and enclosure to pouch and sheath. Virginia Woolf said, “Life is a luminous halo, a semi-transparent envelope surrounding us from the beginning.” She ditched hers by walking into a river with her pockets full of rocks.

Example Sentences

See Examples For:

envelope envelopes

Days later, an envelope arrived on Bancel’s desk.

From The Wall Street Journal ● Aug. 22, 2026

The researchers say they still do not know exactly how APOE2 stabilizes the nuclear envelope and strengthens DNA repair.

From Science Daily ● Jul. 24, 2026

“Tragically, a southern pacific rattlesnake was hiding under the brown padded envelope and bit Addy’s left hand,” the family wrote on the fundraising page.

From Los Angeles Times ● Jul. 21, 2026

This is the movie inside the final red envelope.

From MarketWatch ● Jul. 18, 2026

It was two weeks later that a small boy delivered a scented envelope to the side door; inside in slanted purple letters was a single line, “Jan is home.”

From "The Hiding Place" by Corrie ten Boom

At a box in the back of the shop, there is a stack of envelopes filled with gift vouchers that can be picked up by anyone.

From BBC ● Aug. 22, 2026

The effort, according to internal communications reviewed by ProPublica and an agency tech specialist familiar with the work, focuses on comparing signatures on ballot envelopes with signatures on other election documents, such as registration forms.

From Salon ● Jul. 17, 2026

County Recorder Justin Heap said there was nothing nefarious about the removal, and his staff was taking back equipment his office had paid for, alongside empty, voided ballot envelopes.

From The Wall Street Journal ● Jul. 5, 2026

Researchers think these thick gaseous envelopes may have formed when the planets were much farther from their star, in colder regions of the protoplanetary disc where gas could rapidly accumulate around a solid planetary core.

From Science Daily ● Jun. 27, 2026

Tamika’s hands paused in stuffing envelopes as she raised her brows in my direction.

From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas

Related Words

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