envelope

American  

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

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.

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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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Etymology

Origin of envelope

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

Example Sentences

If you don’t have one readily available, you can also use small envelopes or cardboard boxes glued onto a piece of foam board.

From Salon

Her father had written the word "Liar" on the envelope.

From BBC

"Exosomes are like envelopes with important information," said Ibrahim, associate professor in the Department of Cardiology in the Smidt Heart Institute and first author of the paper.

From Science Daily

In October, I thumbed through snapshots my mother had stashed in albums, envelopes and shoeboxes.

From The Wall Street Journal

They are handed an envelope from Santa containing a letter from a viewer asking how he can show his "leading lady" he loves her through food.

From BBC

Related Words

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