Of Scottish origin: Anglicized form of two different Gaelic names, Cinaed and Cainnech. The former was the Gaelic name of Kenneth mac Alpin (d. 858), first king of the united Picts and Scots. The latter survives today in Scotland as the common Gaelic name Coinneach. Since early in the 20th century Kenneth has been in regular use and enjoyed great popularity as a given name well beyond the borders of Scotland.
German: from the Middle High German title of nobility herzoge ‘duke’ (Old High German herizoho, from heri ‘army’ + ziohan ‘to lead’, a calque of the Byzantine title stratēlatēs ‘general’, ‘commander’, from Greek stratos ‘army’ + elaunein ‘to lead’). The name is unlikely to refer to descent from an actual duke; it is normally an occupational name for the servant of a duke or a nickname for one who put on the airs and graces of a duke.