One of the seven streams from which Ossiriand got its name (S/123). This name is an extension of legol “running free” (Ety/LEK). Given the river’s location in Ossiriand, this name might be Nandorin instead.
Conceptual Development: In its first appearances in Silmarillion drafts from the 1930s, this river was named Loeglin, revised to Legolin (SM/135). In The Etymologies from the 1930s, the name Ilk. Legolin was designated Ilkorin, with the derivation given above (Ety/LEK). Like many of the river names in Ossiriand, Tolkien did not give a new etymology of the name after he abandoned the Ilkorin language.