agnomen

The term "agnomen" refers to an additional cognomen, or surname, given to a person by the ancient Romans, often in honor of an achievement. This practice was distinct from the regular surname, which is a name shared by members of a family and can indicate lineage, residence, occupation, or personal characteristics. While surnames are inherited and common to a family, an agnomen was a special designation. The concept of surnames developed at different times across cultures, with some becoming mandatory as late as the 20th century.12