'subside' originates from Latin, specifically the word 'subsīdere,' where 'sub-' meant 'under' and 'sīdere' meant 'to settle.'

'subsīdere' transformed into the French word 'subsider,' and eventually became the modern English word 'subside' through Middle English.

Initially, it meant 'to settle down or sink,' but over time it evolved into its current meaning of 'to become less intense or severe.'