Ailsa is named for Ailsa Craig — a small island in the Firth of Clyde, Scotland, whose granite was used to make curling stones. The island's name is from the Old Norse Alfsigesey, meaning "island of Alfsigr."
Ailsa is widely used in Scotland and rising in popularity. Outside Scotland it remains rare but distinctive.
Ailsa 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.
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In Pythagorean numerology the letters of Ailsa reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.