A seal, as of a letter.
- A mark or quality, as of distinction, individuality, or authenticity: "Federal courts have a certain cachet which state courts lack” ( Christian Science Monitor).
- A seal on a document, such as a letter.
- A commemorative design stamped on an envelope to mark a postal or philatelic event.
- A motto forming part of a postal cancellation.
- A kind of wafer capsule formerly used by pharmacists for presenting an unpleasant-tasting drug.