The name Nan Dungortheb is translated as "Valley of Dreadful Death", containing the word nan ("valley").
Sindarin
nan dungortheb
place name. Valley of Dreadful Death
Elements
Word Gloss nan(d) “vale, valley, vale, valley, [ᴱN.] dale; [N.] wide grassland; [G.] field acre” donn “swart, swarthy; shady, shadowy” gorthob “horrible” Variations
- Dungortheb ✧ LB/348; LR/299; LRI/Nan-dungorthin
Nan Dungortheb
Nan Dungortheb
The valley in Beleriand where the spider-children of Ungoliant dwelled, translated “Valley of Dreadful Death” (S/81). The initial word of the name is nan(d) “valley” (SA/nan(d)), but the second word is difficult to analyze. Its second element gortheb could be a variant of gorthob “horrible” or it could contain a variant of gurth “death”. The first element Dun- is hard to reconcile, however, as there are no attested Sindarin words of this form meaning anything like “dread” or “death”. Based on its earlier definitions, it might be a variant of [N.] donn “shadowy”; see below.
Conceptual Development: In the earliest Lost Tales, this name was G. Nan Dumgorthin “Land of the Dark Idols” (LT2/35). In the Lays of Beleriand from the 1920s, the form Dungorthin emerged (LB/148), and in the Silmarillion drafts from the 1930s, this valled was named Ilk. Nan Dungorthin (LR/261), which was designated an Ilkorin name in The Etymologies and translated “Vale of Black Horror” (Ety/DUN, NAD, ÑGOROTH). At this stage its initial element was dunn “black” (Ety/DUN), whose Noldorin form was N. donn “shady, shadowy” (EtyAC/DUN).
In Silmarillion revisions from the 1950s-60s, the name was revised to Nan Dungortheb (MR/127) and given its new translation “Valley of Dreadful Death” (MR/297, footnote), but none of the published material explains how the new name and translation correspond. Absent further evidence, N. donn is my best guess for the element Dun- in this name.