Heraldic labels are used to differentiate the personal coats of arms of members of the royal family of the United Kingdom from that of the monarch and from each other.

Therefore, in the English royal family, cadency marks were used from the time of Henry III, typically a label or bordure alluding to the arms of the bearer's mother or wife.

After about 1340, when Edward III made a claim to the throne of France, a blue label did not contrast sufficiently with the blue field of the French quarter of the royal arms; accordingly most royal cadets used labels argent: that of the heir apparent was plain, and all others were charged.

Besides being used as mere temporary marks of cadency, labels are also employed as permanent distinctions, borne (like any other charge) by every member of some particular branches of certain families.

The sons and daughters of the sovereign all bear labels of three points argent; that of the arms of the Prince of Wales is plain, but all others are charged.