Merriam-Webster's Collegiate® Dictionary, 11th Edition
ADDER
I. 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
the common venomous viper ( Vipera berus ) of Europe, any of several North American snakes (as the hognose snakes) that are harmless but are popularly believed to be venomous,
II. noun
Date: 1580
one that adds