1911 Encyclopedia Britannica
A name for the common viper (Vipera cevus ), ranging from Wales to Saghalien island, and from Caithness to the north of Spain. The puff-adder (Bitis s. Echidna arietans ) of nearly the whole of Africa, and the death-adder (Acanthophis antarcticus) from Australia to the Moluccas, are both very poisonous (see Viper). The word was in Old Eng. noedre, later nadder or naddre; in the 14th century "a nadder" was, like "a napron," wrongly divided into "an adder." It appears with the generic meaning of "serpent" in the older forms of many Teutonic languages, cf. Old High Ger. natra; Goth. nadrs. It is thus used in the Old Eng. version of the Scriptures for the devil, the "serpent" of Genesis.
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Chisholm, Hugh, General Editor. Entry for 'Adder'. 1911 Encyclopedia Britanica. https://www.studylight.org/encyclopedias/eng/bri/a/adder.html. 1910.