Abigail is from the Hebrew Avigayil ("my father's joy"). The biblical Abigail — wife of the churlish Nabal of Carmel and, after his death, of King David (1 Samuel 25); her intercession with David is among the most diplomatic moments in the Hebrew Bible.
Abigail 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 Abigail reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.