'sunbathe' originates from the combination of 'sun' and 'bathe', where 'sun' refers to the star at the center of our solar system and 'bathe' means to immerse in water or light.

'sunbathe' was formed in the 19th century by combining 'sun' and 'bathe', reflecting the practice of bathing in sunlight.

Initially, it meant 'to bathe in sunlight', and this meaning has largely remained the same in modern usage.