#lantë (1) noun "fall" in Noldolantë, q.v. Also lanta.
Quenya
lantë
noun. fall
lantë
fall
lantë
falling
lantë (2) adj.? participle? "falling" (MC:214; this is "Qenya" - in Tolkien's later Quenya lantala)
lanta
fall
lanta (1) noun "a fall" (DAT/DANT (TALÁT) ), also lantë.
lanta-
fall
lanta- (2) "fall" (DAT/DANT (TALÁT), Narqelion, VT45:26, VT49:54); lantar aorist tense pl. (Nam, RGEO:66); pl. pa.t. lantaner "fell" (pl.) (SD:246); lantier "they fell", a plural past tense of lanta- "fall" occurring in LR:47; read probably lantaner in LotR-style Quenya, as in SD:246. Also sg. lantië "fell" (LR:56); read likewise *lantanë? (The forms in -ier, -ië seem to be properly perfects.) Future tense lantuva, VT49:47. Participle lantala "falling" (with locative ending: lantalassë) in Markirya.
lanta-
verb. to fall, to fall; [ᴱQ.] to drop
The Quenya verb for “to fall”, dating all the way back to the Qenya Lexicon of the 1910s, though in that document it had the form ᴱQ. lant- and the additional gloss “drop” (QL/51). In the Qenya Lexicon it was derived from the early root ᴱ√LANTAN [LṆTṆ], but in The Etymologies of the 1930s Tolkien changed the root {ᴹ√LANTA >>} ᴹ√DA(N)T “fall down” as the basis for ᴹQ. lanta- “to fall” (Ety/DAT; EtyAC/LANTA). Q. lanta- “fall” appeared regularly in Tolkien’s later writings as well (MC/222; PE17/62; VT49/47), most notably in the Namárië poem in its first phrase: ai! laurië lantar lassi súrinen “ah! like gold fall the leaves in the wind” (LotR/377).
The word lanta was occasionally used as a noun for “a fall”; see that entry for discussion.
Neo-Quenya: In Tolkien’s later writings, lanta- was used only for intransitive “fall”. However, we have no Quenya verbs for transitive “drop” other than 1910s ᴱQ. lant-, so I would assume that lanta- can be used this way as well for purposes of Neo-Quenya (QL/51). For example, lantan “I fall” vs. lantan i macil “I drop [make fall] the sword”.
lantar
fall
-r plural ending used on verbs with a plural subject (VT49:48, 50, 51), e.g. lantar "fall" in Namárië (with the plural subject lassi "leaves"), or unduláver as the pl. form of undulávë "licked down, covered" (PE17:72). The ending is sometimes missing where we might expect it; for instance, the verb tarnë "stood" has multiple subjects and yet does not appear as *tarner in PE17:71.
A noun for “fall” appearing as an element of the title Noldolantë “Fall of the Noldor” (S/87).
Neo-Quenya: The word lasse-lanta “leaf-fall” (LotR/1107) indicates the noun for “a fall” should be lanta, which is also how the noun appears in The Etymologies of the 1930s (Ety/DAT). However, there is an alternate form lassewinta “leaf fall” in drafts of the Lord of the Rings appendices (PM/376) where the second element seems to be the infinitive of the verb winta-, so perhaps lasselanta also includes the infinitive of the verb lanta- “to fall”.
The form lantë more strongly resembles other Quenya nouns, which more often end in -e rather than -a. As such, I prefer lantë over lanta as the independent noun for “a fall”.