(stronghold of Melkor) Udûn
Noldorin
udûn
place name. Udûn
udûn
place name. Udûn
udûn
place name. Dark Pit
Udûn
utumno
(stronghold of Melkor) Udûn
udûn
hell
(= Utumno, stronghold of Melkor), pl. Uduin if there is a pl. (which is unlikely if Udûn is a proper name)
udûn
utumno
band
hell
1) band (i mand, o mband; construct ban) (custody, prison, safekeeping, duress, doom), pl. baind (i mbaind), coll. pl. bannath. 2) Udûn (= Utumno, stronghold of Melkor), pl. Uduin if there is a pl. (which is unlikely if Udûn is a proper name)
band
hell
(i mand, o mband; construct ban) (custody, prison, safekeeping, duress, doom), pl. baind (i mbaind), coll. pl. bannath.
fatanyu
hell
fatanyu noun "hell" (GL:51)
Utum
noun. Utumno
Melkor's first stronghold. The primitive form is given as Utubnu, derived from a stem TUB (LR:394), not defined as such but yielding a series of words that suggest a basic meaning "deep, lowlying". The prefixing of the stem-vowel is a common feature in strengthened primitive forms; the ending -nu seems to be used nowhere else, but Utubnu is clearly to be understood as "very low [place]". The original cluster bn comes out as m in Nandorin; cf. Quenya Utumno. The development is evidently meant to be _Utubnu > Utumnu > *Utumn > Utum_.
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
utumno
place name. Utumno
band
noun. hell
inthanfog
place name. Hell
band
noun. hell
fatanyu
place name. Hell
mandor
place name. Hell
mandos
place name. Hell
Sindarin name of Morgoth’s fortress Q. Utumno (MR/382) translated “Dark Pit” or “Hell” (RC/297), probably a derivative of the same primitive form ✶Utupnu as its Quenya cognate (MR/69). It was also the name of a plain in Mordor (LotR/928).
Conceptual Development: In the Gnomish Lexicon from the 1910s this name was G. Udum or Uduvna (GL/74), probably derived from the same primitive root ᴱ√TUM(B)U as its (early) Quenya cognate ᴱQ. Utumna (QL/95, LT1A/Utumna). In The Etymologies from the 1930s, N. Udûn had essentially the same form and meaning as the later Sindarin name, though at this stage its primitive form was given as ᴹ✶Utubnu (Ety/TUB).
The vale in Mordor was first called N. Narch or Narch Udûn (SD/34, WR/438).