Lammoth means "the Great Echo", and it is named such because it is where Morgoth and Ungoliant fled after the darkening of Valinor and Morgoth's theft of the Silmarils. Ungoliant lusted for the Silmarils and she attacked Morgoth in order to get them. He let out a great cry, which echoed throughout the north of Middle-earth (as it is told in the Silmarillion):
"Ungoliant had grown great, and [Morgoth] less by the power that had gone out of him; and she rose against him...Then Morgoth sent forth a terrible cry, that echoed in the mountains. Therefore that region was called Lammoth, for the echoes of his voice dwelt there ever after, so that any who cried aloud in that land awoke them, all the waste between the hills and the sea was filled with a claumour as of voices in anguish. The cry of Morgoth in that hour was the greatest and most dreadful that was ever heard in the northern world."
Other versions of the legendariumEdit
In Of Tuor and his Coming to Gondolin the name instead refers to the acoustic properties of the location and the natural reverberations they cause. When Fëanor landed there in the First Age, "the voices of his host were swelled to a mighty clamour" by the Echoing Mountains.