Caelan is an anglicized spelling of the Irish Caolan, a diminutive of the word caol, so it means "slender" or "narrow". It belongs to the same family as Kellan and Keelan and became popular in the United States during the Celtic name revival of the 1990s. Caelan stood at number 1283 in 2000, peaked at number 1068 in 2001 and has settled in the 2000s since; in 2025 it ranks number 2892 with 43 births.