The Prose Edda 1.20

Then said Gangleri: "Who are the Æsir, they in whom it behoves men to believe?" Hárr answered: "The divine Æsir are twelve." Then said Jafnhárr: "Not less holy are the Ásynjur, the goddesses, and they are of no less authority." Then said Thridi: "Odin is highest and eldest of the Æsir: he rules all things, and mighty as are the other gods, they all serve him as children obey a father. Frigg is his wife, and she knows all the fates of men, though she speaks no prophecy,—as is said here, when Odin himself spake with him of the Æsir whom men call Loki:

Thou art mad now, Loki, and reft of mind,— Why, Loki, leav'st thou not off? Frigg, methinks, is wise in all fates, Though herself say them not!

Odin is called Allfather because he is father of all the gods. He is also called Father of the Slain, because all those that fall in battle are the sons of his adoption; for them he appoints Valhall and Vingólf, and they are then called Champions. He is also called God of the Hanged, God of Gods, God of Cargoes; and he has also been named in many more ways, after he had come to King Geirrödr:

We were called Grímr and Gangleri, Herjann, Hjálmberi; Thekkr, Thridi, Thudr, Udr, Helblindi, Hárr.

Sadr, Svipall, Sann-getall, Herteitr, Hnikarr; Bileygr, Báleygr, Bölverkr, Fjölnir, Grímnir, Glapsvidr, Fjölsvidr.

Sídhöttr, Sidskeggr, Sigfödr, Hnikudr, Alfödr, Atrídr, Farmatýr; Óski, Ómi, Jafnhárr, Biflindi, Göndlir, Hárbardr.

Svidurr, Svidrir, Jálkr, Kjalarr, Vidurr, Thrór, Yggr, Thundr; Vakr, Skilfingr, Váfudr, Hroptatýr, Gautr, Veratýr."

Then said Gangleri: "Exceeding many names have ye given him; and, by my faith, it must indeed be a goodly wit that knows all the lore and the examples of what chances have brought about each of these names." Then Hárr made answer: "It is truly a vast sum of knowledge to gather together and set forth fittingly. But it is briefest to tell thee that most of his names have been given him by reason of this chance: there being so many branches of tongues in the world, all peoples believed that it was needful for them to turn his name into their own tongue, by which they might the better invoke him and entreat him on their own behalf. But some occasions for these names arose in his wanderings; and that matter is recorded in tales. Nor canst thou ever be called a wise man if thou shalt not be able to tell of those great events."