Portia is the English form of Porcia — feminine of the Roman gens name Porcius (from porcus, "pig"). A top-1000 US baby name since 1980. Portia (Merchant of Venice, c. 1596) — Shakespeare's heroine; a Renaissance heiress who disguises herself as a male lawyer to argue Antonio's case in court against Shylock; her "The quality of mercy is not strain'd" speech (Act IV, Scene 1) is among the most-quoted passages in Western legal literature. Considered one of Shakespeare's most-intellectually independent heroines; the role is among the most-coveted on the English stage. Portia Catonis (Porcia Catonis) (c. Portia Doubleday — Mr. Robot. Portia White (1911-1968) — Canadian contralto.
Portia 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 Portia reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.