Amon Gwareth

Amon Gwareth was the hill that stood in the valley of Tumladen, within the Encircling Mountains, on which Turgon built the city of Gondolin.

Etymology

Amon Gwareth is Sindarin. It has meant "Hill of Watching", from amon "hill" and gwareth "watching", since its first conception. Christopher Tolkien wrote that his father later changed the name to Amon Gwared but this change did not make it in the published Silmarillion. Gwared fited better the gerundic form of Sindarin verbs.