The name Ailsa is a girl's name of Scottish origin meaning "elf victory". Ailsa and is often added to lists like British Girl Names and discussed in our forums with posts like "Girls Makeover - Two Middles".
From the experts:
Ailsa is a traditional Scottish name for girls related to a rocky island in the Firth of Clyde called Ailsa Craig. It might make an interesting alternative to the outdated Ashley or overly popular Ella, and could also be thought of as a relative of Elizabeth or Elsa.
Some other Ailsa relatives: Ailis, Ailse, Ailsha, Allasa, Elsha, Elshe.