envelopes (n)

I folded the letter in half and put it in an envelope.
Send a self-addressed envelope for our free catalogue.
The stack of envelopes on the desk contained important documents awaiting distribution.
She carefully sealed the wedding invitations in elegant envelopes adorned with a wax seal.
The office manager organized the incoming mail into individual envelopes for each department.
The postman delivered a bundle of colorful envelopes, bringing birthday wishes and greetings to the household.