'incendiarism' originates from Latin, specifically the word 'incendium,' where 'incend-' meant 'to set on fire.'

'incendium' transformed into the French word 'incendiarisme,' and eventually became the modern English word 'incendiarism' through Middle English.

Initially, it meant 'to set on fire,' but over time it evolved into its current meaning of 'the act of arson.'