An Etymological Dictionary of the German Language/Annotated/Rüde
Rüde, masculine, ‘hound,’ from Middle High German rüde, masculine, ‘big hound,’ Old High German rudo, hrudeo; Old High German *rutto (compare Modern High German dialectic Rütte) is by chance not recorded, but it may be assumed from the equivalent Anglo-Saxon ryÞÞa, hryþþa, masculine. Their origin is not certain, especially as it cannot be determined whether the initial h of the Anglo-Saxon word is permanent; we have probably to assume Gothic *ruÞja, masculine. Akin to Anglo-Saxon roðhund?.