This word replaced the preposition uin “of the” in the third version of the King’s Letter, appearing in the phrase nelchaenen ned Echuir “the thirty-first day of Stirring”. Both Carl Hostetter (VT31/30) and David Salo (SG/229) theorized that this replacement has a similar prepositional function, from either √NOT “count” or √NED “middle”. Fiona Jallings suggested it might be a temporal preposition, with sense “during” (FJNS/349).
On VT47/40, note 67, Patrick Wynne suggested that this word might be a cognate of the newly published Quenya word net(ë) “one more”. This theory is supported by the most likely interpretation of nelchaenen. This word seems to mean “thirtieth” rather than “thirty-first”, and Patrick Wynne suggested that nelchaenen ned means “thirtieth and one more” = “thirty-first”. I find this theory the most compelling, and use it here.
The ususal Sindarin word for “first” appearing in notes from the late 1960s, replacing more archaic †mein that was a direct cognate of Q. minya “first” (VT42/10, 25). It is a combination of min “one” and the adjectival suffix -ui.
Conceptual Development: The word N. ereg “first” appeared in Lord of the Rings drafts of the 1940s as the initial version of the river-name S. Erui (TI/312). The Etymologies of the 1930s had various rejected words for “first” tied to variations on Firstborn as a title of the Elves: N. edhen “first” under rejected entry ᴹ√EDE or ᴹ√EDEL “precede, come forward” (EtyAC/EDE) and N. seth “first” {>> “forth”} under rejected ᴹ√SET “precede forward” (EtyAC/SET). The Gnomish Lexicon of the 1910s had G. thegra “first, foremost” related to G. thegor “chief” (GL/72).