A wyvern or wivern; is a legendary winged reptilian creature with a dragons head, wings and often two legs or sometimes none, and a barbed tail. The wyvern is found in heraldry. There exists a purely sea-dwelling variant, termed the Sea-Wyvern which has a fish tail in place of a barbed dragons tail. Two of these mythical sea beasts form the supporters of the arms of West Dorset District Council. Wyverns are mentioned in Dante Alighieris Inferno (Canto XVII) as the component body for the poems Geryon.

The usual spelling wyvern (older wivern too) is not attested before the 17th century as winged two-footed dragon'. It is an alteration of Middle English wyvere, wyver (13th century), loanword of Old French wivre (French guivre and vouivre), itself from Latin vipera ;viper, adder, asp, altered in Proto-French to *wipera by Germanic influence (see Old High German wipera).