'arousal' originates from the verb 'arouse,' which comes from Middle English 'arousen,' derived from Old French 'arouser,' meaning 'to stir up.'

'arouser' transformed into the Middle English word 'arousen,' and eventually became the modern English word 'arouse,' leading to the noun form 'arousal.'

Initially, it meant 'to stir up or awaken,' but over time it evolved into its current meaning of 'being awake or excited.'