kleefzegels

Kleefzegels are adhesive seals or stamps used to indicate prepayment or authorization on mail, packaging, or documents. They are applied by removing a backing and pressing the sticky surface onto a surface. Most kleefzegels carry a denomination, the issuing authority, and often imagery or security features. While many kleefzegels function as postage stamps, the term covers a broader category of adhesive seals used in postal, fiscal, and commercial contexts, including revenue stamps and tamper‑evident packaging seals.

Etymology and scope: The Dutch word kleefzegel literally means "sticky seal." The more familiar term for mail stamps is postzegel, but kleefzegels can refer to any adhesive seal used beyond ordinary postage.

History: The shift from wax seals to pre‑paid mail began in the 19th century. Early kleefzegels used moisture‑activated gum that was moistened prior to affixing. In the late 20th century, self‑adhesive formats became common, reducing the need to lick the stamp. Governments also issued adhesive revenue or tax stamps with a similar concept for fiscal purposes.

Usage today: Kleefzegels appear on letters and parcels, and on official documents to show that fees have been paid or that a document has been authenticated. In modern philately, the term remains generic for adhesive stamps, including postage stamps, fiscal stamps, and security seals used on packaging.