An Etymological Dictionary of the German Language/Annotated/Kette
Kette (1.), feminine, ‘covey,’ with the earlier variants kitte, kütte, at present dialectic; used in Modern High German only of partridges, &c. Kette is a corruption of the unintelligible kütte, Middle High German kütte, Old High German chutti, neuter, ‘herd, troop’; compare Middle Low German küdde, Dutch kudde, feminine, ‘herd.’ We might connect the word with Lithuanian gũtas, masculine, gaujà, feminine, ‘herd,’ and hence further with the Indian root jû (for gū̆), ‘to drive, urge on,’ Lithuanian gùiti, ‘to drive.’ Therefore the dental of the Old High German word, as in the equivalent Lithuanian gũtas, belongs to the suffix. The Aryan root is gu, ‘to drive cattle.’
Kette (2.), feminine, ‘chain, fetter,’ from the equivalent Middle High German kęten, kętene (Kette is found since the 15th century), feminine, Old High German chętina, chętinna, feminine, ‘chain’; borrowed from Latin catêna, yet hardly from the latter itself, since the word was probably naturalized in German before the High German permutation of consonants (compare Kerker), but rather from a vernacular cadéna (thus Provençal and Spanish, hence French chaine, from which Middle English chaine, English chain is derived), which by a change of accent and by the High German permutation and mutation resulted in chętîna; Dutch keten and Middle Dutch ketene still point, however, to the t of the Latin word. For the transition of ê to î, compare feiern and Pein. The accent is changed, as in Old High German ábbā̆t, from Latin abbát-em.