The Americana series was a series of United States definitive postage stamps issued between 1975 and 1981. Denominations ranged from one cent to five dollars. It superseded the Prominent Americans series, and was in turn superseded by the Great Americans series and the Transportation coils. The series consisted of twenty stamps issued in sheets, twelve issued in coils, and one produced especially for a booklet.

A definitive stamp is a postage stamp that is part of the regular issue of a country's stamps, available for sale by the post office for an extended period of time and designed to serve the everyday postal needs of the country. The term is used in contrast to a "provisional stamp", one that is issued for a temporary period until regular stamps are available, or a "commemorative stamp", a stamp "issued to honor a person or mark a special event" available only for a limited time. Commonly, a definitive issue or series includes stamps in a range of denominations sufficient to cover current postal rates. An "issue" generally means a set that is put on sale all at the same time, while a "series" is spread out over several years, but the terms are not precise. Additional stamps in a series may be produced as needed by changes in postal rates; nevertheless some values may be permanently available, regardless of prevailing rates; examples include 1c or 1p and $1 or £1.