Ορισμός και Σημασία του "postmark"

What is a "postmark"?

A postmark is a mark or stamp placed on a piece of mail by the postal service to show the date and location where the item was sent. It typically appears on the envelope or package and can include the name of the post office, the date of mailing, and sometimes the time. Postmarks are used to track the journey of mail and serve as proof of when and where it was mailed. They are often applied to letters, packages, and postcards as part of the mailing process and may be either hand-stamped or machine-applied.