Uin was a great whale in the service of Ulmo, who used to drag Tol Eressëa towards Valinor in the earlier versions of the legendarium. Uin also pulled Ulmo's fishy cart,, and is said to be the "primeval whale". Uin does not appear in any later version of the legendarium, and his role seems to have been merged with Ulmo himself.
 In other stories
Uin is a character in Tolkien's Roverandom. In the story, written down in 1927, the great whale Uin takes the enchanted dog Roverandom (formerly known as Rover) to and from the Deep Blue Sea to visit the wizard Artaxerxes.:25 Whilst staying with the mer-people, Uin takes Roverandom on adventures through the seas: Uin takes Roverandom through the Shadowy Seas to the Bay of Fairyland beyond the Magic Isles where Rover saw the Mountains of Elvenhome and the light of Faery. Roverandom thought he could see the white glint of a city of Elves on a green hill far away in the distance.:73-4
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Book of Lost Tales Part One
- ↑ J.R.R. Tolkien, "Qenyaqetsa: The Qenya Phonology and Lexicon", in Parma Eldalamberon XII (edited by Carl F. Hostetter, Christopher Gilson, Arden R. Smith, and Patrick H. Wynne), p. 97
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Book of Lost Tales Part One, Appendix: Names in the Lost Tales – Part One
- ↑ J.R.R. Tolkien, "I-Lam na-Ngoldathon: The Grammar and Lexicon of the Gnomish Tongue", in Parma Eldalamberon XI (edited by Christopher Gilson, Arden R. Smith, and Patrick H. Wynne)
- ↑ 5.0 5.1 J.R.R. Tolkien; Christina Scull, Wayne G. Hammond (eds.), Roverandom