The Gnomish Lexicon of the 1910s had G. drui or drû “wood, forest”; Tolkien specified it was not used of wood a material (GL/31). This Gnomish word may be related to the root ᴱ√TUÐU “kindle”; see that entry for details. In Early Noldorin Word-lists it appeared as ᴱN. dron “wood” (PE13/142).
Early Noldorin
taur
noun. forest
taur-na-fuin
place name. Deadly Nightshade
tavros
masculine name. Lord of Forests
aulos
noun. forest
dron
noun. wood
dâ
adjective. high
tathrin
noun. willow
tîr
noun. king
See later N. Taur-na-Fuin and S. Taur-nu-Fuin for discussion.