From The Collaborative International Dictionary of English v.0.48:
Viperoidea \Vi`per*oi"de*a\, Viperoides \Vi`per*oi"des\, n. pl.
[NL. See Viper, and -oid.] (Zool.)
A division of serpents which includes the true vipers of the
Old World and the rattlesnakes and moccasin snakes of
America; -- called also Viperina.