- the common European viper, Vipera berus.
- any of various other venomous or harmless snakes resembling the viper.
- a person or thing that adds.
- a common viper, Vipera berus, that is widely distributed in Europe, including Britain, and Asia and is typically dark greyish in colour with a black zigzag pattern along the back
- any of various similar venomous or nonvenomous snakes
- a person or thing that adds, esp a single element of an electronic computer, the function of which is to add a single digit of each of two inputs
