'illustrate' originates from Latin, specifically the word 'illustrāre,' where 'in-' meant 'into' and 'lustrāre' meant 'to light up.'

'illustrāre' transformed into the French word 'illustrer,' and eventually became the modern English word 'illustrate' through Middle English.

Initially, it meant 'to light up or make clear,' but over time it evolved into its current meaning of 'to provide visual representation or explanation.'