The Collaborative International Dictionary
water snake
Water moccasin \Wa"ter moc"ca*sin\ (Zo["o]l.) A venomous North American snake ( Ancistrodon piscivorus) allied to the rattlesnake but destitute of a rattle. It lives in or about pools and ponds, and feeds largely of fishes. Called also water snake, water adder, water viper.
WordNet
water snake
n. any of various mostly harmless snakes that live in or near water