meneg (#probably “thousand”) + groth (“large underground dwelling”)
Menegrothnoun. thousand caves
menegrothplace name. Thousand Caves, Thousand Caves or Delvings
Conceptual Development: The name Ilk. Menegroth appeared in Silmarillion drafts from the 1930s (LR/114, LR/220), and was designated as Doriathrin [Ilkorin] in The Etymologies, where it had essentially the same derivation as given above (Ety/ROD).