nassë

noun. nature, true-being; material; person, individual, nature, true-being, *essence; person, individual; material

This word had various uses in Tolkien’s later writings. In notes from around 1959 it was glossed “material” = the substance of which all things are composed (NM/249-250), but later Tolkien used the term erma for “matter” (MR/338, 349). In notes probably from the 1960s, Tolkien use nasse to mean “nature” or “true-being” (PE17/174-175), and in notes from the late 1960s he used it to mean “a person, an individual” (VT49/30).

Neo-Quenya: For purposes of Neo-Quenya, I would use nasse for “nature, true-being, ✱essence”.