'Arnold' originates from Old High German, specifically the name 'Arnolt'/'Arnold', where 'arn' meant 'eagle' and 'wald' meant 'ruler' or 'power'.

'Arnold' changed from Old High German 'Arnolt' and was Latinized as 'Arnoldus' in medieval records; via Norman French forms (e.g. 'Arnoul'/'Arnaud') it entered Middle English and became the modern English 'Arnold'.

Initially, it meant 'eagle-ruler' (combining 'eagle' and 'rule'), but over time it evolved into a personal name and later also into a surname and place-name.