'non-conventional' originates from the prefix 'non-' meaning 'not' and the word 'conventional', which comes from Latin 'conventionem', meaning 'a coming together, agreement'.

'conventionem' transformed into the Old French word 'convention', and eventually became the modern English word 'conventional'.

Initially, 'conventional' meant 'pertaining to an agreement or contract', but over time it evolved to mean 'based on or in accordance with what is generally done or believed'.