n 1  :  the common venomous European viper of the genus Vipera (V. berus) : broadly  :  a terrestrial viper of the family Viperidae  2  :  any of several No. American snakes (as the hognose snakes) that are harmless but are popularly believed to be venomous .
 
 
 
Similar sounding terms:  atria  at·tar 
 
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