German Mythology. the destruction of the gods and of all things in a final battle with evil powers: erroneous modern translation of the Old Icelandic Ragnarǫk, meaning “fate of the gods,” misunderstood as Ragnarökkr, meaning “twilight of the gods.”.
(italics) the final opera of Richard Wagner's The Ring of the Nibelung.
1875-80; < German, equivalent to Götter, plural of GottGod + Dämmerung twilight
from German Götterdämmerung, literally "twilight of the gods," used by Wagner as the title of the last opera in the Ring cycle; used in English from 1909 in the figurative sense of "complete overthrow" of something.