@@@ per Elaran, a “false compound”, originally an apositional genitive Aur Galadh, which explains the lack of mutation
Sindarin
orgaladh
noun. fourth day of the Númenórean week, day of the White Tree
orgaladh
noun. Day of the Tree, *Tuesday
Cognates
- Q. Aldëa “*Tuesday, Tree-day (Númenórean)” ✧ LotR/1110
Elements
Word Gloss or- “-day” galadh “tree”
orgaladhad
noun. fourth day of the Elvish week, day of the Two Trees
This day was renamed orgaladh in the Númenórean calendar
oraearon
noun. seventh day of the Númenórean week, Sea-day
orbelain
noun. sixth day of the week, day of the Powers or Valar
orgilion
noun. first day of the week, day of the Stars
calan
noun. day, period of actual daylight
Attested in the first edition of LotR, but omitted from the second.
oranor
noun. second day of the week, day of the Sun
orithil
noun. third day of the week, day of the Moon
ormenel
noun. fifth day of the week, Heavens' day
penninor
noun. last day of the year
aur
noun. day, sunlight, morning
calan
daytime
(i galan, o chalan), pl. celain (i chelain)
edinor
anniversary day
(pl. edinoer). Archaic edinaur. In ”Noldorin”, the word appeared as edinar.
aur
day
aur (morning), pl. oer. As prefix or- in names of weekdays.
aur
day
(morning), pl. oer. As prefix or- in names of weekdays.
This day was formerly called orgaladhad in the Elvish calendar