Wyvern folklore is rarely fire-breathing like the four-legged dragon. Sometimes modern fantasy book and media authors have wyverns that are frost-breathing or poison-breathing instead of fire-breathing. The current spelling "wyvern" is not attested before the seventeenth century as "winged two-footed dragon". According to the Oxford English Dictionary, it is an alteration of Middle English "wyver" (attested thirteenth century), from Anglo-French "wivre" (cf. French "guivre" and "vouivre"), which originate from Latin "vīpera", meaning "viper", "adder", or "asp". Conversely, medievalist William Sayers proposes a more complex origin for the term. He notes that the Anglo-French "guivre" and its Middle English derivative ceased to
Star (heraldry) Register, vol 1 p 188), while the Ordinary of Arms produced by a late 19th century Lyon King of Arms 'modernizes' the original as "Az. three mullets arg. ...". In Canadian heraldry the usual term is "mullet", but there is also the occasional six-pointed "star" (e.g. in Vol. IV, at p. 274 and in online version of the Canadian Public Register), which is what others would blazon as a six-pointed "mullet". The United States Army Institute of Heraldry, the official heraldic authority in the United States, uses the term "mullet" in its blazons, but elsewhere, as in US government documents