thumb|right|290px|A cachet (on the left) commemorating [[George Washington Carver on a first day cover issued in the United States ]]
thumb|right|290px|George W. Linn's cachet (in the lower left corner) on Harding Memorial issue
In philately, a cachet () is a printed or stamped 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 both official and private (independent of postal authorities) cachets.
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