A noun G. adhwen “approach, avenue” appeared the Gnomish Lexicon of the 1910s near another word G. {anda >>} anna “door” (GL/17, 19). Remnants of this word can also be seen in a torn page of the Gnomish Lexicon Slips, where all that remains is [...]en with the gloss “approach”, with its primitive form ᴱ✶adu̯en- also given (PE13/108). There is no root ᴱ√AD in the contemporaneous Qenya Lexicon, but this word might be an early manifestation of ᴹ√AD “gate, enter” from The Etymologies of the 1930s (Ety/AD).

Neo-Sindarin: For purposes of Neo-Sindarin, I would adapt this word was ᴺS. anwen “approach, avenue”, derived from a combination of √AN “towards” and √MEN “way”, where [nm] became [nw].