(pl. Rodyn, coll. pl. Rodonnath)
Sindarin
rodyn
noun. alternate name of the last day of the Eldarin six-day week
rodon
noun. Vala
rodon
vala
balan
noun. Vala, Vala, [N.] Power, God
The Sindarin equivalent of Q. Vala, derived from the root √BAL “powerful, mighty” and having a plural form Belain (PE17/48). This plural appears as an element in the day-name Orbelain “✱Day of the Valar [Friday]” (LotR/1110). However, in a 1972 Letter Tolkien said this was actually a phonetic adaptation of the Quenya day-name Q. Valanya, an adjective (“✱of the Vala”) not existing in Sindarin (Let/427), presumably because it conflicts with the plural of Balan.
Conceptual Development: N. Balan “Power, God” (both male and female) appeared in The Etymologies of the 1930s under the root ᴹ√BAL with a Noldorin-style plural Belein or Belen (Ety/BAL). The (nasal-mutated) Sindarin-style plural appeared in the name N. Cerch iMbelain “Sickle of the Gods” under the entry for ᴹ√KIRIK (Ety/KIRIK).
Earlier still, in the Gnomish Lexicon of the 1910s, Tolkien had both G. Ban “a god” (GL/21) and G. Gwala “one of the Gods, including their divine folk and Children, hence often used of one of the lesser folk as opposed to Ban” (GL/44). The first of these was derived from the early root ᴱ√VANA having to do with beauty (QL/99) and the second from the early root ᴱ√gwal “fortune, happiness” (GL/44). The entry for Ban was deleted from the Gnomish Lexicon itself, but presumably these two early words were blended into later N./S. Balan.
balan
vala
(i Valan), pl. Belain (i Melain). In ”Noldorin”, the pl. form used with the article was "iMbelain" (LR:365 s.v. KIRIK).
A Sindarin term for the Vala (PE17/33), appearing in its plural form S. Rodyn as one of the days of the week (LotR/1110) and also in the Sindarin name for Valinor: Dor-Rodyn (MR/200). It is derived from the prefixal form rod- of raud “noble” (PE17/118, 186). Its final element might be the augmentative suffix -on, perhaps literally meaning “✱Most Noble”. It could also be the agental suffix -on, as suggested by David Salo (GS/283), but that suffix is usually masculine (WJ/400), whereas Rodon seems to apply to all Valar.