Ciarán (Irish spelling) or Ciaran (Scottish Gaelic spelling) is a traditionally male given name of Irish origin. It means "little dark one" or "little dark-haired one", produced by appending a diminutive suffix to ciar ("black", "dark"). It is the masculine version of the name Ciara. The name became common in reference to Ciar, son of Fergus mac Róich, who gave his name to the Ciarraige and County Kerry, and two early Irish saints both counted among the Twelve Apostles of Ireland: Ciarán the Elder and Ciarán the Younger.
https://en.wikipedia.org/wiki/Ciar%C3%A1n