Aurvandill (Old Norse) is a figure in Germanic mythology. In Norse mythology, the god Thor tosses Aurvandill's toe – which had frozen while the thunder god was carrying him in a basket across the Élivágar rivers – into the sky to form a star called Aurvandils-tá ('Aurvandill's toe'). In wider medieval Germanic-speaking cultures, he was known as Ēarendel in Old English, Aurendil in Old High German, Auriwandalo in Lombardic, and possibly as 𐌰𐌿𐌶𐌰𐌽𐌳𐌹𐌻 (auzandil) in Gothic. An Old Danish Latinized version, Horwendillus (Ørvendil), is also the name given to the father of Amlethus (Amleth) in Saxo Grammaticus' Gesta Danorum.

Comparative studies of the various myths where the figure is involved have led scholars to reconstruct a Common Germanic mythical figure named *Auza-wandilaz, meaning 'light-beam' or 'ray of light'. According to the Old English and Gothic sources, and to a lesser degree the Old Norse text (where a star is mentioned without additional details), this figure seems to have personified the 'rising light' of the morning, possibly the Morning Star (Venus). However, the German and Old Danish evidence remain difficult to interpret in this model.

The Old Norse name Aurvandill stems from a Proto-Germanic form reconstructed as *Auza-wandilaz, *Auzi-wandalaz, or *Auzo-wandiloz. It is cognate with Old English Ēarendel, Old High German Aurendil (≈ Orentil), and Lombardic Auriwandalo. The Gothic word auzandil, which can be read in the Gothica Bononiensia according to the interpretation of several experts, is probably another cognate.

The exact meaning of the Proto-Germanic name has been the subject of sustained scholarly discussion. Most scholars favour a connection with dawn-light imagery, making Aurvandill a figure associated with brightness, the morning star, or a celestial phenomenon.

A commonly cited interpretation understands *Auza-wandilaz as a compound meaning 'light-beam' or 'ray of light', by deriving the prefix *auza- from Proto-Germanic *auzom ('shiny [especially of liquids]'; cf. ON aurr 'gold', OE ēar 'wave, sea'), and *-wandilaz from *wanđuz ('rod, cane'; cf. Goth. wandus, ON vǫndr). The latter probably stems from the root *wanđ- ('to turn, wind'), carrying connotations of suppleness and flexibility, that is, something that bends or moves with ease.

On this basis, Proto-Germanic *Auza-wandilaz may be interpreted as denoting the 'Morning Star' (Venus) or more broadly the 'rising light of the morning' (sunrise), a meaning that would be semantically parallel to Latin lūcifer ('light-bringer, morning star'). Among its cognates, this theory is supported by the Old English figure Ēarendel, whose name is associated with the concept of 'rising light'. Ēarendel has been variously translated as 'radiance, morning star', or as 'dawn, ray of light', and is attested as a rendering of Latin lūcifer. Additional evidence may be provided by the Gothic word auzandil, which translates the Koine Greek word heōsphóros ('dawnbringer') from the Septuagint, itself rendered in Latin as lūcifer. In Old Norse tradition, Aurvandill is likewise connected with a star, though its identity remains uncertain.

Other etymologies have been suggested. One hypothesis derives the name from a Pre-Proto-Germanic form *h₂au̯sro-u̯óndh-elo-s ('the one wandering in the early morning'), yielding translations such as 'shining wanderer' or 'wandering light'. However, this poses phonological difficulties, since Gothic sound laws would have produced **aurawandils rather than auzandil(s). Stefan Schaffner has alternatively posited an original form *h₂au̯s-ont-eló-s ('the little one rising in the morning'), with a diminutive suffix -eló.

A different line of interpretation takes the prefix aur- from Proto-Germanic *aura- ('mud, gravel, sediment'; cf. ON aurr 'wet clay, mud', OE ēar 'earth'), rendering the name as 'gravel-beam' or 'swamp-wand'. According to philologist Christopher R. Fee, this may imply the idea a phallic figure related to fertility, since the name of Aurvandill’s spouse in myth, Gróa, literally meaning 'Growth'.