Pero (Πηρώ) was the Pylian princess, daughter of King Neleus. Her father set the cattle of Phylacus as the bride-price — won by the cunning Bias after his brother Melampus, the seer, was thrown in prison while trying to steal them.
Featured in Homer's Odyssey Book 11 and Pindar.
Pero 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 Pero reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.