Source : Webster's Revised Unabridged Dictionary (1913)

Aye-aye \Aye"-aye`\, n. [From the native name, prob. from its
   cry.] (Zo["o]l.)
   A singular nocturnal quadruped, allied to the lemurs, found
   in Madagascar ({Cheiromys Madagascariensis}), remarkable for
   its long fingers, sharp nails, and rodent-like incisor teeth.

Source : WordNet®

aye-aye
     n : nocturnal lemur with long bony fingers and rodent-like
         incisor teeth closely related to the lemurs [syn: {Daubentonia
         madagascariensis}]