Katelynn is one of the many American spellings of Kaitlyn, the anglicized form of the Irish Caitlín, which in turn comes from Catherine and is usually explained as "pure". The double-n ending gave the name a distinct look during the Kaitlyn boom of the 1990s. Katelynn stood at number 229 in 2000, its peak, and dropped out of the US top 1000 in the 2010s; it ranks number 2736 in 2025.