A coat of arms is a unique heraldic design on a shield, surcoat, or tabard. A surcoat, and subsequently a coat of arms was used by medieval knights to cover, protect, and identify the wearer. The coat of arms on an shield forms the central element of the full heraldic achievement which consists of shield, supporters, crest,and motto. The design is a symbol unique to an individual person or family (except in the UK), corporation, or state. Such displays are commonly called armorial bearings, armorial devices, heraldic devices, or simply arms.Sometimes the term coat of arms is used to refer to the full achievement, but this usage is wrong in a strict sense of heraldic terminology.