Source : Webster's Revised Unabridged Dictionary (1913)

Nero \Ne"ro\, n.
   A Roman emperor notorius for debauchery and barbarous
   cruelty; hence, any profligate and cruel ruler or merciless
   tyrant. -- {Ne*ro"ni*an}, a.

Source : WordNet®

Nero
     n : Roman Emperor notorious for his monstrous vice and fantastic
         luxury (was said to have started a fire that destroyed
         much of Rome in 64) but the Empire remained prosperous
         during his rule (37-68) [syn: {Nero Claudius Caesar
         Drusus Germanicus}, {Lucius Domitius Ahenobarbus}]