Union Jack Union Jack The Union Jack, or Union Flag, is the national flag of the United Kingdom. The flag also has an official or semi-official status in some other Commonwealth realms: for example, it is a ceremonial flag in Canada by parliamentary resolution, and known there as the Royal Union Flag. Further, it is used as an official flag in some of the smaller British overseas territories. The Union Flag also appears in the canton (upper left-hand quarter) of the flags of several nations and territories that are former British possessions or dominions, as well as the state flag of Hawaii.
Union Jack commonly called the Union Jack" nor any pendants or colours used by the King's ships. Reinforcing the distinction the King's proclamation of the same day concerning the arms and flag of the United Kingdom (not colours at sea) called the new flag "the Union Flag". The size and power of the Royal Navy internationally at the time could also explain why the flag was named the "Union Jack"; considering the navy was so widely utilised and renowned by the United Kingdom and colonies, it is possible that the term "jack" occurred because of its regular use on all British ships