'serene' originates from Latin, specifically the word 'serenus,' where 'serenus' meant 'clear, calm, or unclouded.'

'serenus' transformed into the Old French word 'serain,' and eventually became the modern English word 'serene' through Middle English.

Initially, it meant 'clear or unclouded,' but over time it evolved into its current meaning of 'calm and peaceful.'