'century-old' originates from the Latin word 'centuria,' meaning 'a group of 100,' combined with the Old English word 'eald,' meaning 'old.'

'centuria' transformed into the French word 'centurie,' and eventually became the modern English word 'century,' combined with 'old' to form 'century-old.'

Initially, it meant 'a group of 100 years,' but over time it evolved into its current meaning of 'having existed for 100 years.'