|Tell me, who are you, alone, yourself and nameless? - Tom Bombadil|
This article describes a concept which is mentioned in J.R.R. Tolkien's works, but was never given a definite name.
The Troll's Cave was the hideout of the three trolls that captured Bilbo and the dwarves. After Gandalf had rescued Thorin and his party, he reminded them that the trolls must have a cave or hole to hide in from the sun. Searching about, they followed the marks of stony boots uphill to a big stone door. Pushing and incantations by Gandalf did not open it. Then Bilbo asked if the key he had found would help. It did.
The cave floor had bones and an untidy litter of plunder, from brass button to pots of gold. On shelves was a good deal of food, along with a barrel of ale. Clothing of victims hung on the walls as well as several swords. There was also a horrible smell in the air.
The party took much of the food, the barrel of ale, and the gold. Gandalf and Thorin took two swords with beautiful scabbards and jeweled hilts, and Bilbo took a knife in a leather sheath (which for a hobbit was as good as a short sword). Outside the cave the party ate and rested, and then buried the pots of gold near the river with many spells put over them.
Later in Rivendell it was Elrond who read the runes on the swords of Gandalf and Thorin. He revealed that they were very old and had been made by the High Elves of the West, in Gondolin. Thus from the troll’s cave Thorin obtained Orcrist the Goblin-cleaver and Gandalf got Glamdring the Foe-hammer. Much later Bilbo would name his short sword from the troll’s cave "Sting".