Quinn comes from the Irish surname Ó Cuinn, meaning "descendant of Conn" — where Conn itself comes from the Old Irish conn, meaning "wisdom," "counsel," or "chief." It was traditionally a male surname before becoming an increasingly female given name in the late twentieth century.
Quinn is unisex in current use but is given to girls more often than boys in the U.S. Today it sits in the U.S.
Quinn 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 Quinn reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.