Antonia is the feminine of Antonius, an ancient Roman family name of uncertain Etruscan origin. Folk etymology associates it with the Greek anthos (flower) or the Latin sense "priceless." Antonia Minor, mother of Emperor Claudius, was the most famous Roman Antonia.
Today Antonia is widely used across Italy, Spain, Germany, and Eastern Europe. In the U.S. it sits in the top 700.
Antonia 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 Antonia reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.