'oaken' originates from Old English, formed from the noun 'āc' (meaning 'oak') with the adjectival suffix '-en' meaning 'made of or pertaining to'.

'oaken' developed from Old English forms such as 'āc-en'/'ācen', passed into Middle English as 'oaken', and remained into modern English as 'oaken'. The noun 'oak' itself comes from Old English 'āc' and Proto-Germanic *aiks.

Initially it meant 'made of oak' and that core meaning has largely remained the same; by extension it can also describe the characteristic strength or appearance associated with oak.