Meaning From Celtic origin meaning 'war, strife' largely used in French and Irish. Origin of Cillian Celtic , Irish Popular Middle Names Breckin, Everett, Gannon, James, John, Michael, Padraig, Paul, Robert Pronunciation 🔊 Listen Cillian SIL-i-AN Similar Names Kylian Killian Braden Ceallach Callaghan Callahan Oisin Kellach Damarcus Jamarcus Year by Year Popularity of Cillian