Katelyn is an English spelling of the Irish Caitlín, which is a form of Catherine and so means "pure", from the Greek katharos. The many spellings of the name, from Kaitlyn to Caitlin, together made it one of the defining girls' names of the 1980s and 1990s in America. Katelyn ranked number 54 in 2000, peaked at number 52 in 2001 and has since fallen out of the top 1000, landing at number 1077 in 2025.