Ancalagon's name means "jaws-rushing" in Sindarin elvish. Anca means "jaws"; the root alak- (also found in swan) means "rushing". He is called Ancalagon the Black. He was the greatest of the dragons, winged and black.
Using Beren-(Valar)'s Lore Book for Quenya elvish, "jaws" might be anak. "Rushing" could be "flying" rimpa, "swift" arauca, "wrath, violence, haste" orme; -khor and gor.
Salmar-(Valar) suggests that Ancalagon is derived from the Quenya for dragon: Anguloke, angu (from ango "serpent") and loke "dragon".
Thus, attempts at possible alternate names for role-playing are:
Ancalagon, Ancalagon the Black, Ancalak, Anakrimpa, Anakarauca, Anakorme, Anakhor, Anakgor, Anguloke, Anakalak, Jawsrushing, and (really reaching) Swanjaw.
He is mentioned in the Fellowship of the Ring, when Gandalf is discussing the One Ring and fire in "The Shadow of the Past". Gandalf says:
"It has been said that dragon-fire could melt and consume the Rings of Power, but there is not now any dragon left on earth in which the old fire is hot enough; nor was there ever any dragon, not even Ancalagon the Black, who could have harmed the One Ring, the Ruling Ring, for that was made by Sauron himself."In the Great Battle of Valar, Maiar, and Edain versus Melkor and his followers at the fortress of Thangorodrim, the greatest of the dragons is Ancalagon. In the Silmarillion, "Of the Voyage of Earendil", it is said:
"But he (Morgoth) loosed upon his foes the last desperate assault that he had prepared, and out of the pits of Angband there issued the winged dragons, that had not before been seen; and so sudden and ruinous was the onset of that dreadful fleet that the host of the Valar was driven back, for the coming of the dragons was with great thunder, and lightning, and a tempest of fire."Finally the terror of the huge Ancalagon was stopped. As it says in "The Voyage of Earendil":
"Before the rising of the sun Earendil slew Ancalagon the Black, mightiest of the dragon-host, and cast him from the sky; and he fell upon the towers of Thangorodrim, and they were broken in his ruin."References: Fellowship of the Ring, Silmarillion