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

This is the movie inside the final red envelope.

From MarketWatch ● Jul. 18, 2026

This acts like an envelope and all the researchers need to do is change the letter inside before posting it into the body.

From BBC ● Jul. 13, 2026

When the reporter placed a letter for Paxton in the mailbox, an envelope addressed to Warren Paxton, the attorney general’s given name, was visible.

From Salon ● Jul. 7, 2026

"As we look ahead to the upcoming flights, we're poised to open the envelope even further -- moving boldly toward the mission test point this aircraft was built to achieve," Bahm said.

From Science Daily ● Jun. 1, 2026

Jakob jams the letter and envelope into his pocket.

From "The Bletchley Riddle" by Ruta Sepetys and Steve Sheinkin

That could mean setting up a direct debit from your current account to a savings account, organising cash into different envelopes or using round-up tools that put spare change aside when you spend.

From BBC ● Jul. 8, 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

Once he knew we both were in place, we were to hand over our envelopes, which contained the news release the sports world was anticipating.

From The Wall Street Journal ● Jun. 7, 2026

I’m talking about the dusty envelopes hanging from metal hooks near the soup packets.

From Salon ● Jun. 2, 2026

A few had been snatched from envelopes written in the loopy cursive of the coolest granddaughter in world.

From "Look Both Ways" by Jason Reynolds

Related Words

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