Faith comes from the Old French feid, from the Latin fides, meaning "trust" or "belief." It became a Puritan virtue name in 17th-century England, given alongside Hope and Charity (the three theological virtues of 1 Corinthians 13).
Faith entered the U.S. top 1000 in 1880 and has remained continuously. Today it sits in the U.S. top 200 — direct, faithful, with no equivocation.
Faith 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 Faith reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.