'unstructured' originates from the prefix 'un-' meaning 'not' and the word 'structured', which comes from Latin 'structura', meaning 'a fitting together, building'.

'structura' transformed into the Old French word 'structure', and eventually became the modern English word 'structure'. The prefix 'un-' was added to form 'unstructured'.

Initially, 'structured' meant 'to build or arrange', and 'unstructured' evolved to mean 'lacking structure or organization'.