The Collaborative International Dictionary of English v.0.48:

Erinys \E*rin"ys\, n.; pl. Erinyes. [L., fr. Gr. ?.] (Class.
   Myth.)
   An avenging deity; one of the Furies; sometimes, conscience
   personified. [Written also Erinnys.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Erinyes
    n 1: (classical mythology) the hideous snake-haired monsters
         (usually three in number) who pursued unpunished criminals
         [syn: Fury, Eumenides, Erinyes]