wivern(n = noun.person) wyvern - a fire-breathing dragon used in medieval heraldry; had the head of a dragon and the tail of a snake and a body with wings and two legs;
Wivern, n. [OE. wivere a serpent, OF. wivre, guivre, F. givre, guivre, wiver, from L. vipera; probably influenced by OHG. wipera, from the Latin. See Viper, and cf. Weever.].
A fabulous two-legged, winged creature, like a cockatrice, but having the head of a dragon, and without spurs. [1913 Webster]
"The jargon of heraldry, its griffins, its mold warps, its wiverns, and its dragons."
[1913 Webster]