Erica is the feminine of Eric — from the Old Norse Eiríkr ("ever-ruler") — also the Latin botanical name for the heather genus (Erica, 700+ species native to South Africa, Europe, and the Mediterranean). Erica Jong (born 1942) — American author; her 1973 novel Fear of Flying sold 20+ million copies and is credited with mainstreaming feminist literary discourse in the United States; introduced the phrase "zipless fk" to American English. Erica Mena — Love & Hip Hop star. Erika Christensen — Parenthood actress.
Erica 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 Erica reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.