'cask-aged' originates from modern English as a compound of 'cask' and the past-participle adjective 'aged' (from the verb 'age'). 'cask' referred to a wooden container (a barrel) and 'age' refers to the process of maturing.

'cask' changed from Middle English 'caske' (also spelled 'cask') which came from Old North French/Old French 'casque' (with senses including 'helmet' and later 'container'), eventually becoming the modern English 'cask'. 'age' derives from Old French forms such as 'aage'/'aagier' and Middle English developments meaning 'to make older' or 'to mature', yielding the past-participle 'aged'.

Initially, 'cask' had senses tied to containers (and historically even 'helmet'), and 'age' denoted the passage of time or the process of maturing; the compound 'cask-aged' has specifically come to mean 'matured in a cask' in culinary and beverage contexts.