A pale is a term used in heraldic blazon and vexillology to describe a charge on a coat of arms (or flag), that takes the form of a band running vertically down the centre of the shield. Writers broadly agree that the width of the pale ranges from about one-fifth to about one-third of the width of the shield, but this width is not fixed. A narrow pale is more likely if it is uncharged, that is, if it does not have other objects placed on it. If charged, the pale is typically wider to allow room for the objects drawn there.
The word pale originally referred to a picket (a piece of wood much taller than it is wide such as is used to build a picket fence) and it is from the resemblance to this that the heraldic pale derives its name.
A pale may be couped ("cut off" at either end, and so not reaching the top or bottom of the shield); however, while other charges if couped at the top would just be blazoned as "couped in chief," the special term for this in the case of the pale is "a pale retrait" (this also applies to pallets; see below). If couped at the bottom it is blazoned as "a pale retrait in base".
The Canadian pale, invented by Dr. George Stanley for the flag of Canada, occupies fully half the field. On a 1:2 flag such as Canada's, it is square. The name was suggested by Sir Conrad Swan, and used when Elizabeth II of Canada proclaimed the new flag on 28 January 1965.