Uin

Uin was a great whale that served Ulmo, being entitled as the primeval whale.

Etymology
Originally, the Gnomish term uin ("wave", and later "whale"). Another Gnomish for whale is uimoth ("sheep or shepherd of waves"). Moth stands for "sheep" or "1,000", indicating its original meaning of "flock" (e.g. mothweg means "shepherd").

Etymology of Uin greatly resembles Uinen, and her spouse had a cross with the whale for pulling the island.

Other names
Uin was also called Gulma's great whale, with Gulma being an earlier name for Ulmo.

Descriptions
The whale's physical features are rather unclear although according to the Roverandom, Uin was the oldest of the Right Whales (Eubalaena sp.).

Uin was the oldest and mightiest of all whales, and could have been one of the most momentous of all creatures of Ulmo, as the whale was to pull Ulmo's cart. The whale was also left to carry the island of Tol Eressëa across the Sea of Belegaer to off the coast of Bay of Eldamar near Valinor, the Aman's capital. Uin was also in charge to carry important figures.

It was unknown whether Uin was actually one of Ainur to have own shapes like the Great Eagles.

Trivia

 * Narwhals and sea lions also drag the cart of Ulmo.
 * Interestingly, Valar means whales in Swedish Language.
 * It is rather vague whether Uin moved Tol Eressëa all by her/himself or actually co-worked with Ulmo . Although Ulmo certainly participated when he floated the island from the sea bed before moving it.
 * The parcel of Tol Eressëa which was fallen off when Ossë tried to pull back the island westward later became the lands of Ireland on today.
 * In the Middle-earth Role Playing, especially cetaceans are direct realms of Ulmo. Dolphins are called Ulmodil ("friends of Ulmo").
 * Genus Eubalaena means "true  whale" or "good whale" and so on, corresponding with the species name "Right Whale" in some ways. Right whales were historically one of the closest of all whales in terms of relating to human histories. Understandably for New Zealand cultures, right whales, being regarded as "(one of) the most important or symbolic whale to New Zealand", can be seen as an important role in the creation myth of the nation, commonly known as the legend of "Whale Rider". Right whales' curious and playful natures sometimes allow humans and kayaks to ride on their back as well.