'daydreamer' originates from the combination of 'day' and 'dreamer', where 'day' refers to the time of daylight and 'dreamer' refers to someone who dreams.

'daydreamer' evolved from the Middle English word 'day-dream', which was used to describe a reverie or fantasy experienced during the day.

Initially, it meant 'a dream experienced during the day', but over time it evolved into its current meaning of 'a person who indulges in daydreams'.