In heraldry and vexillology, a pale is a charge consisting of a band running vertically down the centre of a shield or flag.[1] 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 depicted there.[1]
The pale is one of the ordinaries in heraldry, along with the bend, chevron, fess, and chief. There are several other ordinaries and sub-ordinaries.[1]
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[2] (see 'pale', English: Etymology 2 on Wiktionary).