This article has no lead section. (October 2018) ( Learn how and when to remove this template message)
The nomen gentilicium, or "gentile name", [i] designated a Roman citizen as a member of a gens. A gens, which may be translated as "race", "family", or "clan", constituted an extended Roman family, all of whom shared the same nomen, and claimed descent from a common ancestor. Particularly in the early Republic, the gens functioned as a state within the state, observing its own sacred rites, and establishing private laws, which were binding on its members, although not on the community as a whole. 
Although the other peoples of Italy also possessed nomina, the distinction between Romans and the non-Roman peoples of Italy disappeared as various communities were granted the Roman franchise, and following the Social War (91–88 BC), when this was extended to most of Italy. Once this occurred, the possession of the nomen gentilicium identified a man as a Roman citizen. 
The nomen was an essential element of Roman nomenclature throughout Roman history, although its usefulness as a distinguishing element declined precipitously following the Constitutio Antoniniana, which effectively granted the nomen "Aurelius" to vast numbers of newly enfranchised citizens. Countless other "new Romans" acquired the nomina of important families in this manner during imperial times; in the fourth century Aurelius was surpassed in number by Flavius, and other names became quite common, including Valerius, Claudius, Fabius, Julius, and Junius. These names no longer had any utility in indicating one's patrilineal ancestry, [ii] and became largely perfunctory. They could be changed to indicate rank or status, and even came to be abbreviated, [iii] much as praenomina had been.  
Both in its original form, identifying an individual as a member of a Roman gens, and in its later form, as an indicator of status, the nomen continued to be used for several decades after the collapse of Imperial authority in the west. The last datable example of a nomen gentilicium belongs to a Julia Rogatiana, who died at Volubilis in AD 655; in the east nomina such as Flavius continued until the beginning of the eighth century; Flavius Basilius was Pagarch of Aphrodito in Egypt in 710. [iv] 
- Although this use of the term gentile has the same origin as the term used to distinguish non-Jews from the Jewish population, its meaning is purely civil, and has nothing to do with ethnic or religious identity; in this use it simply refers to a member of a gens, distinguished by his or her surname, and in this sense the term gentile name is used today without any religious connotation, despite (or perhaps because of) the use of Christian name to refer to personal names. In this sense, Romanized Jews could also be gentiles, and gentiles could be Jewish! This is also the origin of the term gentleman; the association of gentlemen with courtesy developed later.
- Except, of course, for the actual descendants of those ancient noble houses; but as the population of the Roman Empire grew and attained social and political influence, these "old Romans" accounted for a continually decreasing proportion of the overall populace.
- Common abbreviations included Fl. for Flavius, Aur. for Aurelius, Val. for Valerius, and Cl. for Claudius.
- Aphrodito was a pagus in the nome of Aphroditopolis; in Coptic Jkow, in Arabic Kom Ishkaw. The importance attached to the nomen Flavius as an indicator of the bearer's rank is underscored by the fact that Basilius lived more than sixty years after the Arab conquest of Egypt. Other late examples within the Byzantine Empire date to the end of the eighth century.