An Etymological Dictionary of the German Language/Annotated/nähren

by Friedrich Kluge

nähren, verb, ‘to nourish, support, foster,’ from Middle High German nęrn, nęrigen, Old High German nęren, nęrian; properly causative of genesen, hence ‘to cause to recover, make healthy, heal, rescue, keep alive.’ The modern gene is found as early as Middle High German. The word corresponds to Old Saxon nęrian, Anglo-Saxon nęrigan, Gothic nasjan, ‘to rescue.’ The change of s (for z) to West Teutonic and Scandinavian r at the end of the stem in causative verbs is normal (compare lehren); allied to Old Icelandic nœ́ra. See nahrhaft and genesen.