A Wyvern is a dragon that most recognizably has two back legs and two wings. In modern fantasy, wyverns are distinguished as smaller, more animalistic variants of the modern dragon that may or may not have a venomous stinger at the end of their tail. Although the term Wyvern was first conceived during the early 17th century. It was created to distinguish four-legged dragons and two legged dragons/draconic creatures from English and French mythology, as well as the numerous amounts of four-legged and two-legged dragons from bestiaries at the time, in British heraldry. Outside of British heraldry, the distinction would not become prevalent until the late 20th century when fantasy media separated the dragon and wyvern into two distinct creatures.
The word wyvern is derived from the Middle English wyver. This itself is a deviation of the Anglo-French wivre, which comes from the Old North French form of Old French guivre (poisonous snake) and finally originating from the Latin vipera (viper). Alternatively, Medievalist William Sayers theorizes that the word wyvern could've been influenced by the other meaning of guivre (written as wigre): "javelin" or "light spear." Noting the similarity between a snake and a javelin in shape and how javelins were often fletched (thus had avian features), Sayers makes his conclusion based on two factors. Light javelins fell out of favor in the Middle Ages and the usual meaning of guivre was replaced by vipere in French. The two meanings were thus melded together into a mythological creature not thought of before that evolved into the wyvern.
