section_path: Etymology
section_name: Etymology
paragraph_text: Etymology
  
  The English word sun developed from Old English sunne. Cognates appear in other Germanic languages, including West Frisian sinne, Dutch zon, Low German Sünn, Standard German Sonne, Bavarian Sunna, Old Norse sunna, and Gothic sunnō. All these words stem from Proto-Germanic * sunnōn. This is ultimately related to the word for sun in other branches of the Indo-European language family, though in most cases a nominative stem with an l is found, rather than the genitive stem in n, as for example in Latin sōl, ancient Greek ἥλιος (hēlios), Welsh haul and Czech slunce, as well as (with *l > r) Sanskrit स्वर् (svár) and Persian خور (xvar). Indeed, the l -stem survived in Proto-Germanic as well, as * sōwelan, which gave rise to Gothic sauil (alongside sunnō) and Old Norse prosaic sól (alongside poetic sunna), and through it the words for sun in the modern Scandinavian languages: Swedish and Danish sol, Icelandic sól, etc.
  
  The principal adjectives for the Sun in English are sunny for sunlight and, in technical contexts, solar (/ ˈ s oʊ l ər /), from Latin sol —the latter found in terms such as solar day, solar eclipse and Solar System. From the Greek helios comes the rare adjective heliac (/ ˈ h iː l i æ k /). In English, the Greek and Latin words occur in poetry as personifications of the Sun, Helios (/ ˈ h iː l i ə s /) and Sol (/ ˈ s ɒ l /), while in science fiction Sol may be used to distinguish the Sun from other stars. The term sol with a lower-case s is used by planetary astronomers for the duration of a solar day on another planet such as Mars.
  
  The English weekday name Sunday stems from Old English Sunnandæg "sun's day", a Germanic interpretation of the Latin phrase diēs sōlis, itself a translation of the ancient Greek ἡμέρα ἡλίου (hēmera hēliou) 'day of the sun'. The astronomical symbol for the Sun is a circle with a center dot,. It is used for such units as M (Solar mass), R (Solar radius) and L (Solar luminosity).