Cillian is an Irish surname derived from the Gaelic O'Cuilinn, meaning 'descendant of Cuillinn', a personal name thought to be related to the word cuillin, meaning 'noble' or 'exalted'.
In Irish culture, Cillian is often associated with good fortune and prosperity. The name has also been adopted in some Christian traditions as a variant of Julian.
People named Cillian are typically seen as confident, charismatic individuals with a strong sense of justice and a natural ability to lead.
The name Cillian has gained popularity in recent years, particularly in the US and UK, due to its unique and distinctive sound. It is often chosen for its strong Irish heritage and modern appeal.