A term used to describe items of mail on which postage has been either unpaid or short paid or which requires additional postage for delivery. (port dû)
A stamp issued to collect unpaid postage.
Used to collect fees on unpaid/underpaid letters Postmark A mark applied to a letter etc, by the postal authority, to indicate date/time of posting, transit, arrival or special service Precancel A stamp postmarked prior to use in bulk mail preparation
Stamps issued to indicate a penalty for insufficient postage. Postage due stamps are not used to pay postage, yet some issues are known on FDCs. These FDCs were cancelled inadvertently or by favor.
A stamp which is used by the postal authorities to indicate that the correct postal fee has not been paid and the sum due for the delivery of the item. Same as 'To Pay' labels.
Postage due is the term used for mail sent with insufficient postage. While the problem of what to do about letters not paying the full correct fee had existed since the creation of regular postal systems, it was greatly heightened by the advent of postage stamps, since customers were now making their own decisions about the right amount to pay, without the assistance of a presumably-knowledgeable postal clerk.