Abi (אֲבִי) is the Hebrew word for "my father." In 2 Kings 18:2, Abi was the daughter of Zechariah and the wife of King Ahaz — mother of King Hezekiah of Judah.
Used widely in modern Israel.
Abi 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 Abi reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.