[ᴹ]*ᴺ√DIM root. “sad, gloomy”
ᴹ√DEM root. “sad, gloomy”
An Ilkorin-only root in The Etymologies of the 1930s glossed “sad, gloomy” (Ety/DEM). It was first given as √DIM, which Tolkien rejected and replaced by √DEM (EtyAC/DEM), but given the Ilkorin name Dimbar in both The Etymologies and contemporaneous Silmarillion drafts (LR/261), Tolkien likely reversed himself and restored √DIM. In later iterations of The Silmarillion, it is likely that S. Dimbar became a Sindarin name.
References ✧ Ety/DEM; EtyAC/DEM