Home of the Noldor in Eriador during the Second Age, described as the “city of the Elves” (S/286) and translated by Christopher Tolkien as “Fortress of the Eldar” (SI/Ost-in-Edhil). This name is a combination of ost “fortress, city”, the plural in of the definite article i¹ and the plural of Edhel “Elf” (SA/os(t), edhel).