Ragnarok
noun
Rag·na·rok ˈrag-nə-ˌräk 
-rək
: the final destruction of the world in the conflict between the Aesir and the powers of Hel led by Loki
called also Twilight of the Gods
Word History
Etymology
Old Norse Ragnarǫk, literally, fate of the gods, from ragna, genitive plural of regin gods + rǫk fate, course (later rendered as Ragnarøkkr, literally, twilight of the gods)
First Known Use
1770, in the meaning defined above