Location with a lake and falls (S/129, 139), the meaning of this name is unclear.

Conceptual Development: The name ᴱN. Ivrin first appeared in the Lays of Beleriand from the 1920s (LB/60), and N. Ivrin also appeared in Silmarillion drafts from the 1930s (SM/29, LR/260), but there are no clear explanations of its name, or even of the location itself other than its associated lake and falls. In the Gnomish Lexicon from the 1910s, there is an adjective G. ivrin “fertile” (GL/52), but it seems unlikely that it is related. Didier Willis suggested it might mean “*of crystal, crystalline” based on the description of the lake (HSD/ivrin).