Q. #lantë n. “fall”
The word lasselanta “leaf-fall, autumn” (LotR/1107) indicate the form this word should be lanta, which is how it appears in the Etymologies. However, the alternate lassewinta (PM/376) seems to be formed with the infinitive of the verb winta- rather than a noun, so perhaps lasselanta is a similar formation from the verb lanta- “to fall”.
The form lantë, appearing in Noldolantë “Fall of the Noldor” (S/87), more strongly resembles other Quenya nouns, which more often end in -e rather than -a. The noun atalantë “collapse, downfall” is a similar formation from the related verb (ᴹQ.) atalta-, though it could also be the past formation “downfallen” of this TALAT-stem verb.
Reference ✧ S/87 ✧ “fall”