The Collaborative International Dictionary
Wiver
Wiver \Wiv"er\, Wivern \Wiv"ern\, 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.]
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(Her.) A fabulous two-legged, winged creature, like a cockatrice, but having the head of a dragon, and without spurs. [Written also wyvern.]
The jargon of heraldry, its griffins, its mold warps, its wiverns, and its dragons.
--Sir W. Scott. (Zo["o]l.) The weever.
Wiktionary
wiver
n. (context obsolete English) wyvern.