bordure

thumb|150px|A bordure Gules thumb|150px|right|The arms of Thomas de Holland, showing a bordure ermine and bordure argent 150px|right|thumb|The arms of Richard of Conisburgh, 3rd Earl of Cambridge, with a bordure argent semy of lions [[purpure – the lions alluding to those of León in the arms of his mother]] In heraldry, a bordure is a band of contrasting tincture forming a border around the edge of a shield, traditionally one-sixth as wide as the shield itself. It is sometimes reckoned as an ordinary and sometimes as a subordinary.

A bordure encloses the whole shield, with two exceptions: When two coats of arms are combined by impalement, the bordure usually stops at the partition line and does not run down it, as shown in the arms of Kemp as Archbishop of Canterbury in the 15th century; this rule is considered a relic of the older practice of dimidiation. However, a notable exception to this rule can be seen in the arms of Thomas de Holland, Duke of Surrey (a nephew of Richard II) from a drawing of his seal, 1399, showing a differencing of a full bordure ermine, and a full bordure argent. A chief overlies a bordure, unless the bordure is added to a coat that previously included a chief, or so it is often said. In practice, the order in which things are to overlie each other can usually be inferred from the blazon. For example, in the arms of Amber Valley Borough Council, the blazon describes the bordure before the chief, and the bordure does not surround the chief; while in the arms of the British Columbia Institute of Technology, the blazon specifies a chief ... within a bordure.