envelope
/ˈɛnvəˌloʊp/
noun
- A flat paper container used to enclose a letter or document, typically with a flap that can be sealed.
- The office manager ordered a box of business envelopes for the mailroom.
- He wrote the address on the envelope and dropped it in the mailbox.
- She put the birthday card into a white envelope and sealed it.
- A covering or container that surrounds something, such as a protective layer or structure.
- The spacecraft's outer envelope protected it from extreme temperatures.
- The building's glass envelope allows natural light to flood the interior.
- The seed's hard envelope helps it survive harsh conditions.
- The limits or boundaries of something, especially in a technical or figurative sense.
- As an artist, she constantly tries to push the envelope with her experimental work.
- The pilot tested the aircraft's performance envelope during the flight.
- The new design pushes the envelope of what is possible in smartphone technology.