Flavius /ˈfleɪviəs/ was a gens of ancient Rome, meaning "blond". The feminine form was Flavia.
After the end of the popular Flavian dynasty of emperors, Flavius/Flavia became a praenomen, common especially among royalty: the adoption of this praenomen by Constantine I set a precedent for some imperial dynasties, such as Justinian dynasty and in the official names of high-ranking officials (Aëtius, Belisarius). The given name still exists in romance languages, such as the Romanian Flavius or Flaviu, feminine Flavia, and Portuguese Flávio, feminine Flávia.
Read more about Flavius: Gens Flavia