'forever-kept' is a compound word formed from 'forever' and 'kept'. 'Forever' originates from Old English 'forever', meaning 'for all time', and 'kept' is the past participle of 'keep', originating from Old English 'cēpan', meaning 'to seize, hold'.

'Forever' and 'kept' have been used in English since the Middle Ages, and their combination into 'forever-kept' is a modern construct to describe something preserved indefinitely.

The meaning of 'forever-kept' has remained consistent, referring to something preserved indefinitely.