Backstamp
A postmark applied to mail by the receiving post office or by a post office handling the piece while it is in transit. Backstamps are usually on the back of a cover, but they can be on the front as well.
A postmark applied to mail by the receiving post office or by a post office handling the piece while it is in transit. Backstamps are usually on the back of a cover, but they can be on the front as well.
