Last peak of the Mist Mountains (LotR/429), explictly translated “Last Peak” in Tolkien’s “Unfinished Index” of The Lord of the Rings (RC/366). This name is a combination of methed “end” and rass “horn”.
Conceptual Development: In Lord of the Rings drafts from the 1940s, this name first appeared as N. Methen Amon (TI/391), later revised to N. Methendol and finally N. Methedras (TI/404). These earlier forms clearly included the Noldorin adjective N. methen “end, final” (Ety/MET). It is possible that this is true of the initial appearance of N. Methedras as well (as suggested by Roman Rausch, EE/2.63), since phonetically the combination [[n|[nr] became [ðr]]], and Tolkien often represented [ð] as “d” in the Lord of the Rings drafts. For example, N. Caradras >> S. Caradhras underwent the same development.
Unlike Caradhras, however, Tolkien never revised this form to ✱✱Methedhras. This could have been an oversight, or Tolkien could have reconceived of the initial element as the noun methed “end” seen in Methed-en-Glad, as suggested above (and by David Salo, GS/384).
This word is attested in later writings as an element in the names Methed-en-Glad “End of the Wood” and possibly Methedras “Last Peak” (of the Misty Mountains). The latter name first appeared in Lord of the Rings drafts from the 1940s as N. Methen Amon and Methendol (TI/404), making it likely that methed is a revision from the earlier adjective N. methen (Ety/MET).
This new form likely changed from an adjective to a noun, since -ed/-ad is usually a gerundal suffix in Sindarin (forming nouns from verbs). This word is clearly a noun in the name Methed-en-Glad, and could also be a noun in Methedras (= “Peak of the End?”).