Adder

ad′ėr, n. the popular English name of the viper.— ns. Ad′der's-tongue , a genus of ferns the seeds of which grow on a spike resembling a serpent's tongue; Ad′der's-wort , a wort or plant, so called from its being supposed to cure the bite of serpents—also called Snakeweed . [A.S. nædre ; cf. Ger. atter for natter . An adder came by mistake into use for a nadder ; the reverse mistake is a newt for an ewt or eft .]