Agnomen
Pronunciation : Ag*no"men
Part of Speech : n.
Etymology : [L.; ad + nomen name.]
Definition : 1. An additional or fourth name given by the Romans, or account of some remarkable exploit or event; as, Publius Caius Scipio Africanus.
2. An additional name, or an epithet appended to a name; as, Aristides the Just.
Source : Webster's Unabridged Dictionary, 1913