Overprint
（重定向自Surprint）
An overprint is an additional layer of text or graphics added to the face of a postage stamp, banknote or postal stationery after it has been printed. Post offices most often use overprints for internal administrative purposes such as accounting but they are also employed in public mail. The most well-recognized varieties are commemorative overprints which are produced for their public appeal and command significant interest in the field of philately.