From the Roman family name Flavius, meaning golden or blonde-haired.
Flavia is a name worn smooth by two thousand years of use, yet it retains the warmth of its Latin origin: 'flavus,' meaning golden or yellow-haired. It was the feminine form of Flavius, the cognomen of one of Rome's most consequential dynasties. The Flavian emperors — Vespasian, Titus, and Domitian — ruled Rome from 69 to 96 AD, completing the Colosseum, destroying Jerusalem, and surviving the eruption of Vesuvius that buried Pompeii.
Women of the Flavian gens bore Flavia as a mark of lineage, and early Christianity adopted it eagerly: Flavia Domitilla, great-niece of the emperor Domitian, is venerated as a martyr saint, and the Domitilla catacombs beneath Rome bear her name. Through the medieval period Flavia remained alive in Italy and the Romance-speaking world, carried by the Church's veneration of its early martyrs. It never fully crossed into English-speaking countries, which gave it an air of Continental sophistication — the name of a Roman noblewoman, an Italian opera character, or a scholarly heroine.
Dorothy L. Sayers gave the name to characters in her academic fiction, and it appears in various Victorian and Edwardian novels as a signal of classical education and Mediterranean warmth. In Italy and Brazil today Flavia is a living, contemporary name, entirely unselfconscious about its antiquity. For English speakers, it carries the rare quality of being both genuinely historical and surprisingly fresh — a golden name in every sense.