Son of Elrond (LotR/227). This name is translated “Elf-knight”, a combination of archaic Sindarin †Ell “elf” and ro(c)hir “knight” (Let/281-2).
Conceptual Development: In Lord of the Rings drafts from the 1940s, this character was first named N. Elbereth (WR/297). Earlier still, the name Ilk. Elbereth used as a name for a son of Dior (LR/147), but later S. Elbereth was reserved for the Sindarin name of Varda.
el (from CE *eldā- connected or concerned with the stars) + roch (“horse”) + hîr (“master, lord”)