A definitive stamp is a postage stamp

Postage stamp

A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

, that is part of a regular issue of a country's stamps (often referred to as a "regular issue") available for sale by the postal service for an extended period of time. The term is used in contrast with a "provisional stamp

Provisional stamp

Linn's World Stamp Almanac defines a provisional stamp as "a postage stamp issued for temporary use to meet postal demands until new or regular stocks of stamps can be obtained."...

", one that is issued for a temporary period until regular stamps are available, or a "commemorative stamp

Commemorative stamp

A commemorative stamp is a postage stamp, often issued on a significant date such as an anniversary, to honor or commemorate a place, event or person. The subject of the commemorative stamp is usually spelled out in print, unlike definitive stamps which normally depict the subject along with the...

", 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 denomination

Denomination (postage stamp)

:This article deals with the price of a postage stamp. For other meanings of the word 'denomination' see Denomination .In philately, the denomination is the "inscribed value of a stamp"...

s sufficient to cover many or all postal rates usefully. (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.)

Range

The range of values varies by era and country, but the focus is on coverage; the values should be sufficient to make up all possible charges using as few stamps as possible. Generally the smallest value will be the smallest unit of currency, or smallest fractional postal rate; for instance, the 1925 regular issue of the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 included a 1/2-cent stamp because some rates were expressed in fractions of a cent per ounce. The highest value of the series is generally quite large, typically from 50-100 times the normal letter rate; typical values include one pound, five dollars, etc. Not often seen by the average person, they are most common for parcels.

The in-between values are usually chosen to "make change" efficiently, for instance 1, 2, 5, 10, 20, 50 in a decimal currency. It is common to include all values between 1 and 10, multiples of 5 from 10 to 50, and multiples of 10 from 50 to 100. Additional "oddball" values may reflect specific common rates, and if the series lasts for a period of time, there may be a number of such unusual values as in the UK QE II Machin series below.

Definitives are the workhorse stamps of a country, and as such, they tend to be small, with designs reflecting local culture and history. The definitives of poorer countries will often be very plain and cheaply printed, unlike the large and decorative commemoratives, which are almost pure profit if bought by foreign collectors and never used for postage.

Frequency of issue

Since postal administrations know that many stamp collectors want to own every stamp of a definitive series, and a complete series can be quite expensive, there is always the temptation by governmental bureaucrats to make extra money by frequently issuing new definitive sets, as well as including stamps with very high face values in a set. Collectors' organizations have recommended that administrations only bring out new definitive issues no more often than every five years, and most administrations of the world follow this policy. An exception would be the death of a monarch, or other prominent leader, necessitating a new definitive series for the new ruler. Sometimes merely the portrait is changed, and the outer design (known as the frame) remains the same throughout several issues. Countries that ignore frequency of issue guidelines and issue volumes of stamps that have little to no practical usage produce what many collectors refer to as wallpaper.

Collecting

Since definitive series are issued over a period of time and are reprinted to meet postal demand, they often contain more variation than is typically found in stamps that have a single print run. Switching printing methods and experimenting with phosphors is a common source of variation in modern stamps, while differences in watermarks and perforation are also prevalent, especially in older stamps. Many philatelists study these differences as part of their hobby and try to collect all the varieties of each stamp. Some varieties are particularly rare and can be more valuable than others of the same stamp that may look the same to the casual observer. One notable example of this variation is the Machin stamps of the UK, where philatelists have identified over 1000 varieties of the same basic design.

Special stamp

Special stamp

A special stamp is a type of postage stamp typically intended for use on special occasions and holidays that occur repeatedly. Christmas stamps, with a seasonal design, and used in vast numbers to mail Christmas cards, are the most familiar, but in recent years a number of other types have...

s, such as the Christmas stamp

Christmas stamp

Many nations of the world issue Christmas stamps, postage stamps with a Christmas theme and intended for use on seasonal mail such as Christmas cards. These stamps are regular postage stamps, unlike Christmas seals, and are usually valid for postage year-round...

s issued annually by various countries, are sometimes regarded as definitives because they are not commemoratives, but they typically only include a limited range of denominations relating specifically to the mail seen on the occasion for which they are issued.

Notable definitive stamp series

• Argentina
  • 1935-51 Patriots and Natural Resources Issue
• Australia
  • Kangaroo and Map
    Kangaroo and Map
    The Kangaroo and Map is the commonly used name for the first stamp issues of the Australian Commonwealth.They were issued in 1913, over 12 years after Federation. Although the delay had several causes, one of the major reasons was political wrangling regarding the design...
    
    
  • King George V series
• Canada
  • Scroll issue
  • Queen Elizabeth II issue
    Queen Elizabeth II definitive stamp (Canada)
    The Queen Elizabeth II definitive stamp is a domestic rate stamp issued by Canada Post, and bearing the image of Elizabeth II, Queen of Canada. Six versions of the stamp have been issued since 2003....
    
    
  • Arch and maple leaf issue
  • War issue
• France
  • Ceres series
    Ceres series (France)
    The Ceres series was the first postage stamp series of France, issued in 1849 as a representation of the French Republic.The series bore the effigy of Ceres, goddess of growing plants in Roman mythology. Jacques-Jean Barre did the initial drawing and gravure...
    
    
  • Navigation and Commerce issue
    Navigation and Commerce issue
    The Navigation and Commerce issue is a definitive series of French postage stamps issued for the colonial territories of France. It was designed by Louis-Eugène Mouchon....
    
    
• Germany
  • Germania
    Germania (stamp)
    Germania stamps are definitive stamps that were issued by the German Empire and the Weimar Republic between 1900 and 1922, depicting Germania. They represent the longest running series in German philately and are in their many variations and derivations an essential part of German philatelic...
    
    
  • Women in German history series
    Women in German history series
    Women in German history is a definitive stamp series issued in the Federal Republic of Germany and West Berlin from 1986 to 1990, and in reunited Germany since 1990.-Description:...
    
    
• Greece
  • Hermes Heads
    Large Hermes head
    Large Hermes heads is the name used by philatelists to describe the first issue of Greek stamps, issued in 1861 and used until 1886.The stamps depict a profile of the Greek messenger god Hermes in a frame strongly resembling that used for contemporary stamps of France. The first set was issued on...
    
    
• Norway
  • Post horn series, issued since 1872
• Portugal
  • Ceres series
    Ceres series (Portugal)
    The Ceres series of Portuguese postage stamps is a definitive series depicting the Roman goddess Ceres that was issued between 1912 and 1945 in Portugal and its colonies.- History and description :...
    
    
• United Kingdom
  • Wilding series
    Wilding series
    The Wildings were a series of definitive postage stamps featuring the Dorothy Wilding photographic portrait of Queen Elizabeth II that were in use between 1952 and 1967 until they were replaced by the Machin series.- History :...
    
    
  • Machin series
    Machin series
    The Machin series of postage stamps is the main definitive stamp series in the United Kingdom, used since 5 June 1967. It is the second series to figure the image of Elizabeth II, replacing the Wilding series....
    
    
• United States
  • Washington-Franklin Issues
    Washington-Franklin Issues
    The Washington - Franklin Issues are a series of definitive U.S. Postage stamps depicting George Washington and Benjamin Franklin produced by the U.S. Post Office between 1908 and 1922...
    
    
  • Presidential Issue
    Presidential Issue
    The Presidential Issue, nicknamed the Prexies by collectors, is the series of definitive postage stamps issued in the United States in 1938, featuring all 29 U.S. presidents from George Washington through Calvin Coolidge...
    
    
  • Liberty issue
    Liberty Issue
    The Liberty issue was a definitive series of postage stamps issued by the United States between 1954 and 1965. It offered twenty-four denominations, ranging from a half-cent issue showing Benjamin Franklin to a five dollar issue depicting Alexander Hamilton...
    
    
  • Prominent Americans series
    Prominent Americans series
    The Prominent Americans series is a set of definitive stamps issued by the United States Post Office Department between 1965 and 1978....
    
    
  • Americana series
    Americana series
    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...
    
    
  • Great Americans series
    Great Americans series
    The Great Americans series is a set of definitive stamps issued by the United States Postal Service, starting on December 27, 1980 with the 19¢ stamp depicting Sequoyah, and continuing through 2002, the final stamp being the 78¢ Alice Paul self-adhesive stamp. The series, noted for its simplicity...
    
    
  • Transportation coils
    Transportation coils
    The Transportation coils series is a set of definitive stamps issued by the United States Postal Service between 1981 and 1995. Officially dubbed the "Transportation Issue" or "Transportation Series", they have come to be called the "transportation coils" because all of the denominations were...
    
    
  • Distinguished Americans series
    Distinguished Americans series
    The Distinguished Americans series is a set of definitive stamps issued by the United States Postal Service which was started in 2000 with a 10¢ stamp depicting Joseph Stilwell...