A word appearing as ᴱQ. natto “thing, affair” in the Qenya Lexicon of the 1910s, an elaboration of ᴱQ. nat “thing” under the early root ᴱ√NĀ “be, exist” (QL/64). The word reappeared with the glosses “affair, matter, thing” in the English-Qenya Dictionary of the 1920s with a plural nattur indicating a stem form of nattu-, but this entry was deleted (PE15/68).

Neo-Quenya: I’d retain ᴺQ. natto (nattu-) for purposes of Neo-Quenya since both Q. nat “thing” and √NĀ survive in Tolkien’s latter writings, but I would limit its sense to “affair, matter” as in “*a thing that is happening/has happened”.