cognomen

A personal epithet or clan name added to the given name and family name of Ancient Romans.

Julius Caesar's actual name was Gaius Iulius Caesar. Gaius was his praenomen or forename, Iulius his nomen or surname, and Caesar his cognomen, denoting which part of the Iulius family he belonged to.

"Five hundred years or more afterwards, the family migrated to Rome under circumstances of which no trace remains, and here, probably with the idea of preserving the idea of vengeance which we find set out in the name of Tisisthenes, they appear to have pretty regularly assumed the cognomen of Vindex, or Avenger."

Synonym of nickname, any epithet used similar to the Roman cognomina.

In this by-place of nature, there abode, in a remote period of American history, that is to say, some thirty years since, a worthy wight of the name of Ichabod Crane; who sojourned, or, as he expressed it, "tarried," in Sleepy Hollow[…]. The cognomen of Crane was not inapplicable to his person.

Her husband was evidently a sensible man, and he might have given his wife a little more sense than she could have derived from her downright father and her silly mother-in-law, who were really as great a pair of noodles as ever were exhibited in the pages of a modern novel, under the cognomen of "amiable rustics."

Synonym of surname, a family name.

What's in a name? Well, to the Dragons, it would seem rather a lot, as they've tonight committed their cash to personalised products and to the man with the most famous cognomen in confectionery. I'll leave you to look that one up.