The bordure is an heraldic ordinary around the edge of the shield, typically one-eighth to one-twelfth its width. It is subject to most of the standard treatments – embattled, nebuly, &c – though, because no period examples have been attested, the “bordure flory” is considered a step from period practice. Because it has only one edge, a bordure may not be “dancetty”, nor may it be fimbriated, cotised, or voided.
The bordure has no diminutives in present Society heraldry. Some early Society blazons used the term “bordurelet”, as an indication to the artist that the bordure should be skinny; but this is poor practice, and is no longer done.
The addition of a charged bordure is a common way of differencing, both in medieval and Society heraldry. Bordures surmount all other ordinaries except chiefs and cantons. In the case of the chief, we are told the bordure does not run along the bottom edge of the chief, but rather, the chief completely surmounts the bordure [Parker 73]; but we do find exceptions to this rule in period rolls. The use of both chief and bordure is considered at best poor practice, and is disallowed in the Society when the chief and bordure are of the same tincture.
The “bordure denticulada” is an Iberian variant of the bordure embattled, with only the crenellations issuant from the edge of the shield. It is a period charge, found in the arms of Echaurj, mid-16th C. [Armeria 316].
The Prince of the Mists bears: Argent, a crown within a laurel wreath vert, all within a bordure engrailed azure.
Cormacc mac Conaill bears: Sable, a bordure argent.
Aryanhwy merch Catmael bears: Purpure, a bordure ermine.
Teresa de Çaragoça bears: Or, a tree eradicated proper within a bordure denticulada azure.