Rosalee is the modern American spelling of Rosalie — from the Latin rosa (rose) combined with the -lee (Old English lēah, meadow) suffix. A top-500 US baby name since 2014. Saint Rosalia of Palermo — 12th-century Sicilian hermit and patron saint of Palermo; her July 15 feast day is one of the largest religious festivals in Sicily. Rosalie Anderson MacDowell — Andie MacDowell's birth name.
Rosalee 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 Rosalee reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.