A roundel is a circular disc used as a symbol. The term is used in heraldry, but also commonly used to refer to a type of national insignia used on military aircraft, generally circular in shape and usually comprising concentric rings of different colours. Other symbols also often use round shapes.
Main article: Roundel (heraldry)
In heraldry, a roundel is a circular charge. Roundels are among the oldest charges used in coats of arms, dating from at least the twelfth century. Roundels in British heraldry have different names depending on their tincture. Thus, while a roundel may be blazoned by its tincture, e.g., a roundel vert (literally "a roundel green"), it is more often described by a single word, in this case pomme (literally "apple", from the French) or, from the same origins, pomeis—as in "Vert; on a cross Or five pomeis".
One special example of a named roundel is the fountain, depicted as a roundel barry wavy argent and azure, that is, containing alternating horizontal wavy bands of blue and silver (or white).
Main article: Military aircraft insignia
The French Air Service originated the use of roundels on military aircraft during the First World War. The chosen design was the French national cockade, whose colours are the blue-white-red of the flag of France. Similar national cockades, with different ordering of colours, were designed and adopted as aircraft roundels by their allies, including the British Royal Flying Corps and Royal Naval Air Service, and (in the last few months of the war) the United States Army Air Service. After the First World War, many other air forces adopted roundel insignia, distinguished by different colours or numbers of concentric rings.
The term "roundel" is often used even for those military aircraft insignia that are not round, like the Iron Cross-Balkenkreuz symbol of the Luftwaffe or the red star of the Russian Air Force.
Among national flags which display a roundel are the flags of Bangladesh, Belize, Brazil, Dominica, Ethiopia, Grenada, India, Japan, Laos, Niger, North Korea, Palau, Paraguay, South Korea, Tunisia, and Uganda.
Flags for British Overseas Territories used a British Blue Ensign defaced with a white roundel displaying the arms or badge of the dependency until 1999. The same pattern is still used for all the states of Australia except Victoria.
See also: Military aircraft insignia
Some corporations and organizations make use of roundels in their branding.
In December 1914 the RFC followed the example of their French Allies and adopted red, white and blue circles...