Caitilin is an Irish feminine given name meaning "pure maiden" or "fair maiden," derived from the Irish name Caitlín, which combines "cait" meaning pure/virginal and "-lín," a diminutive suffix. It has historical significance, associated with legendary heroine Caitlín Ni Uallacháin, known for her beauty and intelligence. Today, it's popular in English-speaking countries like Ireland and the US, often spelled as Caitlin or Kaitlyn.