sun, n., The bright celestial object which is the chief source of natural light and heat on earth and appears to pass across the sky each day from east to west; the central body of the solar system, around which the earth and other planets orbit, and which by its changing position relative to the earth’s axis determines the seasons.

Summary

A word inherited from Germanic.

Cognate with Old Frisian sunne, sonne, senne (West Frisian sinne, North Frisian sen), Old Saxon sunna (Middle Low German sunne), Old Dutch sunna (Middle Dutch sonne, Dutch zon), Old High German sunna (Middle High German sunne, sonne, German Sonne), Old Icelandic sunna (in poetry), Gothic sunno, Crimean Gothic sune,

< a variant of the same Indo-European base as early Scandinavian (runic: Norway) solu (dative singular), Old Icelandic sól, Old Swedish, Swedish sol, Old Danish, Danish sol, Gothic sauil, and also Sanskrit svar (genitive sūraḥ), Old Avestan huuarə̄, ancient Greek ἥλιος, ἠέλιος (Doric ἀέλιος, Cretan ἀβέλιος; compare helio– comb. form), classical Latin sōl, Old Welsh houl (Welsh haul), Old Prussian saule, Lithuanian saulė, all in sense ‘sun’, and Early Irish, Irish súil eye. — Oxford English Dictionary