The Collaborative International Dictionary of English v.0.48:

Norn \Norn\, Norna \Nor"na\, n. [Icel. norn, pl. nornir.]
   1. (Scandinavian Myth.) Any one of the three Fates, Past,
      Present, and Future. Their names were Urd, Verdandi, and
      Skuld. They are identified with the Anglo-Saxon Wyrd, and
      are similar to the Greek Moirae and Roman Parcae.
      [1913 Webster + WordNet 1.5]

   2. A tutelary deity; a genius.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Norn
    n 1: (Norse mythology) any of the three goddesses of destiny;
         identified with Anglo-Saxon Wyrd; similar to Greek Moirae
         and Roman Parcae [syn: Norn, weird sister]