Octavia comes from the Latin octavus, meaning "eighth." Originally given to the eighth child of a Roman family, it became a Roman cognomen and then a given name.
Octavia has been rising rapidly in the 2010s. Today it sits in the U.S. top 350.
Octavia does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Octavia reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.