Cachet
From Free net encyclopedia
In philately, a cachet is a design or inscription, other than a cancellation or pre-printed postage, on an envelope, postcard, or postal card to commemorate a postal or philatelic event. There are official and private cachets; they commemorate everything from the first flight on a particular route, to the Super Bowl. Cachets are also frequently made, either by private companies, or a government, for First day of issue stamp events or 'Second-Day' stamp events.
Cachets have been made by practically every method by which artwork can be made or reproduced. Cachets have been hand-painted, printed and computer-generated. Frequently flight cachets (which have also been used in space and on the moon) are rubber-stamped.