official stamp applied to a piece of mail to show that postage has been paid
A postage stamp is evidence of pre-paying a fee for
postal services. Usually a small paper rectangle or square that is attached to an
envelope, the postage stamp signifies that the person sending the letter or package may have either fully, or perhaps partly, pre-paid for delivery. Postage stamps are the most popular way of paying for retail mail; alternatives include
prepaid-postage envelopes and
Postage meters.
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