'unclassified' originates from the prefix 'un-' meaning 'not' and the word 'classified' from Latin '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', with 'unclassified' being a negation of this.

Initially, it meant 'not sorted into classes', and this meaning has largely remained the same in modern usage.