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. 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

Ackman himself has a history of pushing the envelope with novel investment ideas and endeavors, not all of which go according to plan.

Read more on The Wall Street Journal

He gave one an envelope of cash he’d saved and told her to take herself to Disneyland.

Read more on Los Angeles Times

“Sometimes I put the money into an envelope and put the envelope at the gate or door area.”

Read more on Los Angeles Times

Solemnly the children would bring the envelope to Mrs. Clarke, who would pat each of them on the cheek and murmur, “Ah, Miss Lumley! I hope she’s getting on all right, poor thing!”

Read more on Literature

They were all from his gentlemen’s club or from various banks, except for one thin, stained envelope with no return address but which bore many colorful postmarks and exotic stamps from distant lands.

Read more on Literature

Related Words

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