0 a flat, usually square or rectangular, paper container for a letter
1 a usually rectangular paper container for a letter:
2 a flat, usually square or rectangular, paper container for a letter:
3 a flat, usually square or rectangular, plastic container used for keeping papers in:
The papers were handed to me in a transparent plastic envelope.
4 to go further than the usual limits by doing something new, dangerous, etc.:
We're really pushing the envelope on this technology; a lot of other companies are just playing catch-up.
Send a self-addressed envelope for our free catalogue.
Do you recognize the writing on the envelope?
The teacher opened the sealed envelope containing the exam papers.
Instead of throwing the old letter away, they used the name and address on the envelope to find Arlene and deliver it to her.
Natural latex is also important as an adhesive in the production of envelopes, labels, sticky tape, and bandages.
People often give money in a red envelope as a present at weddings or the New Year.
