The “Pass of Light” through the Pelóri mountains into the heart of Valinor (S/59). It is a compound of cala “light” and cirya “cleft, pass” (RGEO/62).
Conceptual Development: In Silmarillion drafts from the 1930s, it was called ᴹQ. Kalakilya (LR/173), using an earlier word for “pass”: ᴹQ. kilya (Ety/KIL).
Calacirya place-name "Light-cleft", Calacirya, the great ravine in the mountains of Valinor, the passage leading from Valmar to the region where the Teleri lived. Genitive Calaciryo in Namárië(Nam, RGEO:67)