A word appearing in the Declension of Nouns from the early 1930s glossed “comb, ridge” (PE21/19) and “ridge (comb, crest)” (PE21/27). It perhaps refers to raised formations of various kinds, geological as well as things like the comb or crest of a bird or the ridge of a roof.
Qenya
hahta
noun. heap, pile, (piled) mound
hat
noun. ridge, comb, crest
A noun in The Etymologies of the 1930s glossed “pile, mound” derived from the root ᴹ√KHAG “pile up” (Ety/KHAG). It also appeared in the Outline of Phonetic Development (OP1) from the 1930s with the gloss “heap, piled mound” (PE19/45). In that document it illustrated how combinations of voiced stops were unvoiced so that ᴹ✶khagdā > ✱khakta > hahta. This derivation reappeared in Outline of Phonology (OP2) from the 1950s, but there the root was changed √KHAG >> √KHAB in revisions made in 1959 or later, and a new Quenya form Q. hamna was given (PE19/91-92).
Neo-Quenya: For purposes of Neo-Quenya, I’d use the later form Q. hamna and give Q. hahta its later meaning “fence, hedge” (PE19/91).