A modern coat of arms is derived from the mediæval practice of painting designs onto the shield and outer clothing of knights to enable them to be identified in battle, and later in tournaments.

Modern usage may see these designs as carved or painted ornamentation to buildings and furniture, as printed or embossed images on notepaper and other documents and incorporated as part of a seal. The Great Seal of the United States is often described as being the coat of arms of the United States of America.

A European coat of arms, sometimes known as an achievement or as armorial ensigns or bearings is designed according to the rules of heraldry.

Japanese coats of arms, called kamon (often abbreviated "mon"), are family crests which often date back to the tenth or eleventh century, and are still actively used in Japan today.

The chrysanthemum (kiku in Japanese) is the coat of arms of the Japanese Emperor.