Ciaran is an Irish name, in Irish spelled Ciarán, that means "little dark one", from ciar, black or dark, and a diminutive ending. Two early Irish saints bore the name, among them Saint Ciarán of Clonmacnoise, founder of one of Ireland's great monasteries; Kieran is the anglicized spelling. Ciaran has inched upward in the United States from number 2341 in 2000 to number 1609 in 2025, its best rank yet.