'insolation' originates from Latin, specifically the word 'insolatio,' where 'in-' meant 'in' and 'sol' meant 'sun.'

'insolatio' transformed into the French word 'insolation,' and eventually became the modern English word 'insolation' through Middle English.

Initially, it meant 'exposure to the sun,' but over time it evolved into its current meaning of 'the amount of solar radiation reaching a given area.'