Source : Webster's Revised Unabridged Dictionary (1913)

Viperoidea \Vi`per*oi"de*a\, Viperoides \Vi`per*oi"des\, n. pl.
   [NL. See {Viper}, and {-oid}.] (Zo["o]l.)
   A division of serpents which includes the true vipers of the
   Old World and the rattlesnakes and moccasin snakes of
   America; -- called also {Viperina}.