A word for “valley” or “vale” appearing as an element in many names, mostly referring to wide valleys as opposed to imlad for narrow valleys. As an element in compounds or before another word in names it generally took the form nan as in Mornan “Dark Valley” and Nan Dungortheb “Valley of Dreadful Death”. As an independent word it had the form nand: “In Sindarin this gave nand which as other words ending in nd remained in stressed monosyllables but > nann > nan in compounds” (NM/351). It was a derivative of the root √NAD (NM/351; Ety/NAD).
Conceptual Development: The first appearance of this word was as G. nand or nann “a field acre” where it was probably a derivative of the early root ᴱ√NAŘA [NAÐA] as suggested by Christopher Tolkien (GL/59; LT1A/Nandini). Its use in early names like G. Nan Dumgorthin “Land of the Dark Idols” (LT2/35) and G. Nan Tathrin “Land of Willows” (GL/67; LT2A/Nantathrin) indicates the actual meaning was closer to “land”. The word reappeared as ᴱN. nann or nand “dale” in Early Noldorin Word-lists of the 1920s (PE13/150), consistent with the new gloss “Valley of Willows” for ᴱN. Nan Tathrin in Silmarillion drafts from the late 1920s (SM/35).
The word N. nand or nann “wide grassland” appeared in The Etymologies of the 1930s as a derivative of the root ᴹ√NAD (Ety/NAD), and the word nan(d) “valley” or “vale” was mentioned a number of times in Tolkien’s later notes (PE17/37, 83; RC/269). In notes from the late 1960s it was derived from primitived ✶nandē based on the root √NAD meaning “hollow of structures or natural features more or less concave with rising sides”. In these notes Tolkien said this word was:
> ... originally used only of not very large areas the sides of which were part of their own configuration. Vales or valleys of great extent, plains at the feet of mountains, etc. had other names. As also had the very steep-sided valleys in the mountains such as Rivendell (NM/351).
This note confirms that imlad was the proper word for a steep and narrow valley, but the notion that nand was not used for “valleys of great extent” contradicts its 1930s gloss “wide grassland” (Ety/NAD), as well as its use in names like Nan Dungortheb which were the extensive plains south of Ered Gorgoroth, or in the name Nan-tathren which had no particular boundaries.
Neo-Sindarin: For purposes of Neo-Sindarin, I would ignore Tolkien’s late 1960s notion that this word was not used for large valleys, and apply it to wide valleys and even extensive grasslands between or below mountains, using imlad for narrow valleys and tum for deep (and round) valleys surrounded on all sides.
A valley in the Misty Mountains translated “Dimrill Dale” (LotR/283) or more literally “Vale of (the Region of) Dim Streams” (RC/269, PE17/37). It is itself a translation of Kh. Azanulbizar of similar meaning (LotR/283, TI/166, PE17/35). This name is a combination of nan(d) “valley”, dû “night, dimness”, the lenited form hir of sîr “river, stream”, and the suffix -ion “-region, -land” (PE17/37).
Conceptual Development: In Lord of the Rings drafts from the 1940s, this valley was first named N. Tum Dincelon “Dimrill Dale” (RS/434), later revised to N. Nanduhiriath (TI/174) and finally N. Nanduhirion (TI/166).