The old capital of Gondor, translated “Citadel of the Stars” (LotR/244) or “Fortress of the Stars” (RGEO/65, Let/426). This name is a combination of ost “fortress, city” and the class-plural of gil “star” (RC/232; SA/os(t), gil).
Conceptual Development: When this name first appeared in Lord of the Rings drafts from the 1940s, it was already N. Osgiliath “Fortress of the Stars” (TI/119).
topon. -. >> Ostgiliath