Source : Webster's Revised Unabridged Dictionary (1913)

Eos \E"os\, n. [L., fr. Gr. 'Hw`s.] (Gr. Myth.)
   Aurora, the goddess of morn.

Source : WordNet®

Eos
     n : (Greek mythology) the winged goddess of the dawn in ancient
         mythology; daughter of Hyperion; identified with Roman
         Aurora