Giselle is from the Old Germanic gisil ("pledge, hostage") — a name borne by multiple Carolingian and Frankish princesses. The "mad scene" closing Act I is widely cited as the most-challenging dramatic moment in the ballerina repertoire. Giselle Cole — Star on Fox.
Giselle 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 Giselle reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.