The name is either derived from the Gaelic, keallach, meaning, “strife,” or the word, ceall meaning, “church; monastery.”
Killian is usually the anglicized version and its one of the few Irish names used outside the English speaking world. It has been in usage in Germany, Poland and France, no doubt, due to the associations with the saint.
It was borne by Saint Killian, the author of the Life of St. Bridget, he was also a missionary to Artois and Franconia and is considered the patron saint of Franconia.
In modern day Bavaria, the name is still quite popular, often rendered as Kilian.
The name is also borne by actor Cillian Murphy.
Kelly is occasionally used as a nickname.
The feast day of St. Killian is July 8.
Currently, Cillian is the 21st most popular male name in Ireland, (2010). His rankings in other countries are as follows:
- # 43 (Austria, Kilian, 2010)
- # 62 (Northern Ireland, Cillian, 2010)
- # 62 (Ireland, Killian, 2010)
- # 88 (Germany, Kilian, 2011)
- # 110 (France, Killian, 2009)
- # 173 (France, Kilian, 2009)
- # 763 (United States, Killian, 2010)
Other forms include:
- Quilià (Catalan)
- Killianus (Dutch/Latin)
- Killian (English)
- Kelian (French)
- Kilien (French)
- Kilian (German/French/Polish/Romanian)
- Cillín (Irish-Gaelic)
- Chiliano (Italian)
Obscure feminine forms include:
- Kiliane (French)
- Kiliana (Polish)