Heraldry is the profession, study, or art of creating, granting, and blazoning arms and ruling on questions of rank or protocol, as exercised by an officer of arms.Heraldry comes from Anglo-Norman herald, from the Germanic compound harja-waldaz, "army commander". The word, in its most general sense, encompasses all matters relating to the duties and responsibilities of officers of arms. To most, though, heraldry is the practice of designing, displaying, describing, and recording coats of arms and heraldic badges.

Historically, it has been variously described as "the shorthand of history" and "the floral border in the garden of history." The origins of heraldry lie in the need to distinguish participants in combat when their faces were hidden by iron and steel helmets. Eventually a formal system of rules developed into ever more complex forms of heraldry.

To "blazon" arms means to describe them using the formal language of heraldry. This language has its own vocabulary and syntax, or rules governing word order, which becomes essential for comprehension when blasoning a complex coat of arms. The verb comes from the Middle English "blasoun," itself a derivative of the French "blason" meaning "shield." The system of blazoning arms used in English-speaking countries today was developed by heraldic officers in the Middle Ages. The blazon includes a description of the armourials contained within the escutcheon or shield, the crest, supporters where present, motto and other insignia. Complex rules apply to the physical and artistic form of new creations of arms, such as the Rule of tincture. A thorough understanding of these rules is a key to the art of heraldry. In Europe originally the rules and terminology were broadly similar from kingdom to kingdom, but several national styles had developed by the end of the Middle Ages. Most aspects, however, remain in common.