An escutcheon, or scutcheon, is the shield displayed in a coat of arms. The term "crest" is often used incorrectly to designate this part of the coat of arms. The escutcheon shape is based on the Medieval shields that were used by knights in combat, and varied by region and time period accordingly. Since this shape has been regarded as a war-like device appropriate to men only, British ladies customarily bear their arms upon a lozenge, or diamond-shape, while clergymen and ladies in continental Europe bear theirs on a cartouche, or oval. Other shapes are possible, such as the roundel commonly used for arms granted to Aboriginal Canadians by the Canadian Heraldic Authority. The word escutcheon is derived from Middle English escochon, from Anglo-Norman escuchon, from Vulgar Latin scution-, from Latin scutum, "shield". Derived from its meaning in heraldry, the term "escutcheon" can be used to represent a family and its honour. The idiom "a blot on the escutcheon" is used to mean a stain on somebody's reputation. An inescutcheon is a smaller shield that is shown within or superimposed over the main shield. This may be used for heraldic style, in pretense (to bear another's arms over one's own), to bear one's own personal arms over the territorial arms of his/her domains, or as a simple charge.