A Quenya name of Númenor after its fall into the sea (S/281), it is simply the noun atalantë “collapse, downfall” used as a name (MC/223).
Conceptual Development: The name ᴹQ. Atalante appeared in the earliest tales of the fall of Númenor (LR/11, 25), usually in this form though at least once appearing as Atalantie (Let/347). Its resemblance to the name Atlantis was intentional (Let/347), created as part of the background for Tolkien’s (unfinished) time-travel story about Atlantis: “The Lost Road” (LR/36-104).
collapsed, fell down