The Sword of Elendil that was broken (LotR/243), later reforged as Andúril (LotR/277). This name is a combination of the primitive roots √NAR “fire” and √THIL “white light” (Let/425), and was translated “red and white flame” in the 1966 index of The Lord of the Rings (RC/231).
Conceptual Development: Its Quenya name first appeared as ᴹQ. Narsil in the draft of The Lord of the Rings chapter: “The Battle of the Pelennor Fields” (WR/370, 372 note #14).
Narsil (Þ) noun the sword of Elendil, compound of the stems seen in Anar "Sun" and Isil "Moon"; see Letters:425 for etymology