Rocío is the Spanish word for "dew." The title of the Virgin Mary as Nuestra Señora del Rocío (Our Lady of the Dew) — patron of the Andalusian town of Almonte, whose annual pilgrimage attracts a million people.
Rocío is widely used in Spain and Latin America.
Rocio 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 Rocio reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.