Arago: Regular Definitive Series

Regular Definitive Series

The United States Postal Service issued definitive stamps in sets with clearly defined themes and common design elements throughout most of the twentieth century. During the post-1940 or 'Modern' period, the U.S. Postal Service issued both traditional definitive sets as well as definitive stamps without a common theme, design, or name.

The major definitive series include the Liberty series, the Prominent Americans series, the Americana series, the Great Americans series, Transportation coils, Flora & Fauna series, and the Distinguished Americans series.

The non-traditional definitives—that is, those without a common theme, design, or name—can be broadly categorized as American Culture and Scenes, expedited mail, flags, wildlife, mini-scapes, and rate change issues. These stamps can be found in the catagories of Limited and Regulare Definitive Issues within Arago."

During the Modern period, definitives were issued in a variety of formats including sheets, coils, and booklets with self-adhesive or water-activated gum. They were printed by both private contractors and the Bureau of Engraving and Printing (BEP). A variety of perforation sizes was used and the period ushered in 'die-cut' separations on self-adhesive stamps.

The Postal Service announced in 1995 that future definitive issues for nonprofit bulk mail would be comprised of stamps issued in non-denominated form, their assigned values not printed on their faces.


Juell, Rodney A., and Steven J. Rod, eds. Encyclopedia of United States Stamps and Stamp Collecting. Minneapolis: Kirk House Publishers, 2006.