Jenny is the English diminutive of Jennifer — from the Welsh Gwenhwyfar ("white phantom"), the Welsh form of Guinevere. T. Barnum's 1850 American tour with her grossed the equivalent of $20 million in today's dollars and is considered the foundation of modern celebrity culture. Jenny McCarthy — The View host. Jenny from the Block — Jennifer Lopez (2002).
Subject of countless YA fiction studies.
Jenny 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 Jenny reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.