Flags are usually attached either to poles or flagstaffs. Poles are fixed to buildings or are planted in the ground; flagstaffs are carried. The vertical direction of a flag is called the hoist, and the horizontal direction, or the length from the staff to the free end, is called the fly.

The design or device which often appears in the upper inner corner of a national flag is called the union. This design represents the union of the various states, prov-inces, or colonies of a country under one government. The union of the Flag of the United States has had forty-eight stars in the blue field since July 4, 1912. The union design may sometimes cover a much greater part of a flag than a single corner, as in the flag of Great Britain.

A canton is the upper quarter of a flag nearest the staff. Sometimes the section which contains the union is called the canton.