'oak-covered' originates from the English word 'oak' and the past participle 'covered', where 'oak' refers to a type of tree and 'covered' means 'to be overlaid or surrounded by'.

'oak' and 'covered' have been used in English since Old English times, with 'oak' coming from the Old English 'āc' and 'covered' from the Old English 'cofre'.

Initially, it meant 'to be overlaid by oak trees', and this meaning has largely remained the same in modern usage.