In the fiction of J. R. R. Tolkien, Moria (Sindarin for "Black Chasm") was the name given by the Eldar to an enormous underground complex in north-western Middle-earth, comprising a vast network of tunnels, chambers, mines and huge halls or mansions, that ran under and ultimately through the Misty Mountains. There, for many thousands of years, lived the Dwarf clan known as the Longbeards. The name given to Moria by the Dwarves is Khazad-dûm, which means Delving of the Dwarves.
According to Tolkien's fiction, the city and one-time centre of dwarven industry was also called Hadhodrond (pronounced HATH-o-drond) by the Sindar, Casarrondo by the Noldor and Phurunargian in the Common Speech, all meaning the Dwarrowdelf. For over a thousand years of the Third Age it was widely known as Moria, "Black Chasm" or "Black Pit", from Sindarin mor="black" and iâ="void, abyss, pit".
It has been suggested that Tolkien—an ardent Catholic—may have used this name as a reference to the mountains of Moriah, where (according to the book of Genesis) Abraham was to sacrifice his son, Isaac. However, Tolkien categorically denied such derivations, saying that "As to Moria…it means…Black Chasm . …As for the 'land of Morīah' (note stress): that has no connection (even 'externally') whatsoever."
Read more about Moria (Middle-earth): Further Reading