Phyllis (Φυλλίς) comes from the Greek phyllon, meaning "leaf" or "foliage." In Greek myth, Phyllis is the Thracian princess who hanged herself for love of Demophon and was transformed into an almond tree.
Phyllis peaked at #36 in the U.S. in 1929 and has since declined. The actress Phyllis Diller (1917-2012) was a notable bearer.
Phyllis 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 Phyllis reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.