Tracy is from the Irish surname Ó Treasaigh ("descendant of Treasach," meaning warlike), via Norman French. Famously private — has rarely given interviews or toured since 2009.
Tracy 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 Tracy reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.