Rag·na·rok 
(rägnə-rŏk′)
(rägnə-rŏk′)n.
In Norse mythology, the apocalyptic battle that the gods will fight against the giants before the world perishes in flame and is created anew.
[Old Icelandic Ragnarökkr, Ragnarök : ragna, genitive pl. of regin, the gods (pl.) + rökr, rökkr, twilight or rök, reason, origin, marvel (perhaps originally "twilight of the dawn, rebirth" ); both akin to Old Icelandic rökva, rökkva, to grow dark, and Greek Erebos, Erebus.]