The Hobbit week was taken from the Dunedain and the names were translations of the names given by the Dunedain following the Eldar. The six days of the Eldar already had days dedicated to the Sun, Moon, Stars, the two trees of Valinor, the Sky and the Valar or rulers, in that order being the chief or High day.
The Dunedain kept the dedications and order, but altered the forth day known originally as tree-day with reference to the eldest tree of which a decadence grew in Numenor, and desiring a seventh day week and being great mariners added a Sea-day after the sky day.
The hobbits also took over this arrangement, but the meanings of the days were soon forgotten and then reduced in form. The 'translation' was made more than a thousand years before Bilbo's time. In the oldest records in the shire in the earliest parts of the great writ of Tuckborough, the names appeared in the archaic forms.
|Day Name||Meaning||Relationship to Gregorian calendar|
|Sterday||Stars of Varda||Saturday|
|Trewsday||Two Trees of Valinor||Tuesday|
But in the red book of Westmarch they are written as:
Stirday (or sterday), Sunday, Munday, Trewsday. Hevensday, Mersady. Hiday; and Hevensday was universally pronounced Hensday and often written He'nsday.