1911 Encyclopædia Britannica/Wyvern

WYVERN, or Wivern, the name of an heraldic monster, with the forepart of a winged dragon and the hind part of a serpent or lizard (see Heraldry). The earlier spelling of the word was wiver or wivere; O. Eng. wyvre; O. Fr. wivre, mod. givre. It is a doublet of “viper,” with an excrescent n, as in “bittern,” M. Eng. bitore.