Epithet—a descriptive phrase that expresses a characteristic of the person or thing mentioned. 

It's used to add to a person's or place's regular name and attribute a specific quality to them.

Think about ‘Alexander the Great' or ‘Eric the Red.' 

In literature, Homer famously used epithets like ‘swift-footed Achilles' to enhance the heroic stature of characters.

In your writing or speeches, using epithets can provide clarity, emphasize certain qualities, and add a lyrical quality to your characters.