'nonessential' originates from the prefix 'non-' meaning 'not' and the word 'essential' from Latin 'essentialis', where 'essentia' meant 'being' or 'essence'.

'essentialis' transformed into the Old French word 'essentiel', and eventually became the modern English word 'essential'. The prefix 'non-' was added to form 'nonessential'.

Initially, 'essential' meant 'pertaining to the essence', but over time it evolved to mean 'absolutely necessary'. 'Nonessential' thus came to mean 'not absolutely necessary'.