epithet — as in: earned the epithet, "The Great"
George Washington is known by the epithet, "Father of our Country".
a descriptor added to a person’s name — as in Alexander The Great
a phrase used in place of a name or word — such as:
- The Big Apple for New York
- The Great Emancipator for Abraham Lincoln
- man’s best friend for dog
In botany, a specific epithet or epithet is the word identifying the species.