Philippa is the feminine of Philip — from the Greek philos (loving) and hippos (horse), meaning "lover of horses." Queen Philippa of Hainault (1314-1369) was the consort of Edward III of England.
Philippa Gregory (born 1954) is the British historical novelist (The Other Boleyn Girl).
Philippa 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 Philippa reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.