The Collaborative International Dictionary of English v.0.48:

Eumenides \Eu*men"i*des\, n. pl. [L., from Gr. ? lit., gracious
   goddesses.] (Class. Myth.)
   A euphemistic name for the Furies of Erinyes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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