Middle English, alteration (by incorrect division of a naddre) of naddre, from Old English nǣdre. This word has lost its original initial n through a process that also affected apron and a umpire in the 14th and 15th cents. When it was preceded by the indefinite article, the two words were misinterpreted: a nadder was taken as an adder, and likewise a napron as an apron and a numpire as an umpire. The form nether, preserving the initial n, still exists dialectally. For the opposite process, by which a word has gained an initial n, see note at newt