Sabrina is the Latin name of the River Severn in Britain — and of the legendary nymph who drowned in it. According to Geoffrey of Monmouth, Sabrina was the daughter of a British king, drowned by her stepmother and transformed into the spirit of the river.
Today it sits in the U.S. top 200.
Sabrina 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 Sabrina reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.