'classified' originates from the Latin word 'classificare', where 'classis' meant 'class' and 'facere' meant 'to make'.

'classificare' transformed into the French word 'classifier', and eventually became the modern English word 'classify', from which 'classified' is derived.

Initially, it meant 'to arrange in classes', but over time it evolved into its current meaning of 'designated as secret'.