'rejuvenate' originates from Latin, specifically the Medieval Latin word 'rejuvenare', where 're-' meant 'again' and 'juvenare' derived from 'juvenis' meaning 'young'.

'rejuvenare' changed into the Late Latin/Medieval Latin form 'rejuvenatus' and later entered English as 'rejuvenate' (first recorded in English in the 17th century) with the same basic structure.

Initially it meant 'to make young again' and over time it has kept that core sense while also extending figuratively to mean 'to restore vigour or freshness' in non-living contexts.