I. ad·der ˈa-dər noun
Etymology: Middle English, alteration (by false division of a naddre ) of naddre, from Old English nǣdre; akin to Old High German nātara adder, Latin natrix water snake
Date: 14th century
1. : the common venomous viper ( Vipera berus ) of Europe ; broadly : any of various snakes of the viper family — compare puff adder
2. : any of several North American snakes (as the hognose snakes) that are harmless but are popularly believed to be venomous
[
adder 1
]
II. add·er ˈa-dər noun
Date: 1580
: one that adds ; especially : a device (as in a computer) that performs addition