From Tolkien Gateway
Elvenesse was a term whose meaning is not clearly defined, but which seems to refer to all the lands of the Elves, both west and east of the Great Sea.
The ending -ess (also in Westernesse) was used in romance literature for fictional lands that had partly francized names (as in Lyonesse in Arthurian legends).
- ↑ J.R.R. Tolkien, "Nomenclature of The Lord of the Rings" in Wayne G. Hammond and Christina Scull (eds), The Lord of the Rings: A Reader's Companion, pp. 778-9