An emblem is a pictorial image, abstract or representational, that epitomizes a concept — e.g., a moral truth, or an allegory — or that represents a person, such as a king or saint.

The words emblem and symbol often appear interchangeably in day-to-day conversation without causing undue confusion. A distinction between the two may seem unnecessarily fastidious. Nevertheless, an emblem is a pattern that is used to represent an idea, or an individual. An emblem crystallizes in concrete, visual terms some abstraction: a deity, a tribe or nation, a virtue or a vice. An emblem is an object or a representation of an object.

An emblem may be worn or otherwise used as an identifying badge or patch. A real or metal cockle shell, the emblem of St James the Apostle, sewn onto the hat or clothes identified a medieval pilgrim to his shrine at Santiago de Compostela. In the Middle Ages, many saints were given emblems, which served to identify them in paintings and other images: St Catherine had a wheel, or a sword, St Anthony Abbot a pig and a small bell. These are also called attributes, especially when shown carried by or close to the saint in art. Kings and other grand persons increasingly adopted personal devices or emblems that were distinct from their family heraldry. The most famous include Louis XIV of France's sun, the salamander of Francis I of France, the boar of Richard III of England and the armillary sphere of Manuel I of Portugal. In the fifteenth and sixteenth century there was a fashion, started in Italy, for making large medals with a portrait head on the obverse and the emblem on the reverse; these would be given to friends and as diplomatic gifts. Pisanello produced many of the earliest and finest of these.