* Old English: "sunne"

* Proto-Germanic: "sunnō"

These words are related to Indo-European roots that likely referred to the brightness or heat of the sun.

Therefore, the sun was named "sun" because it was a natural and intuitive name that reflected its most obvious and important qualities. It's simply the word people used to describe the bright, warm star that dominates our sky.

There isn't a specific event or story associated with the naming of the sun, unlike some other celestial bodies. It's a name that emerged naturally from language and observation.