A noun Tolkien described as a “flet” (Middle English for “floor”) applied to the elevated wooden platforms the Elves of Lórien had in trees from The Lord of the Rings (LotR/342). In notes on Words, Phrases and Passages from the Lord of the Rings, Tolkien said its proper meaning was a “flat space, platform” and it was derived from primitive ✶talam (PE17/52). It seems this word applies to an elevated platform without walls, as opposed to a floor within a building which would be [N.] panas (Ety/PAN). In theory the final n of talan would be lost, but it was likely restored by analogy with its plural form telain.
Conceptual Development: This word appeared as N. talan “flet” in Lord of the Rings drafts of the 1940s (TI/227).
pl1. telain** **_ n. _flat space, platform. Q. talan or talma. >> tâl