n 1  :  a pit viper (Agkistrodon contortrix) widely distributed in upland areas of the eastern U.S. that attains a length of three feet (0.9 meter), is coppery brown above with dark transverse blotches that render it inconspicuous among fallen leaves, and is usu. regarded as much less dangerous than a rattlesnake of comparable size  2  :  a very venomous but sluggish Australian elapid snake of the genus Denisonia (D. superba) .
 
 
 
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