Cillian
Meaning
probably Old Irish cell, "church", with a diminutive suffix; famously borne by actor Cillian Murphy
The story
Cillian is probably from the Old Irish cell, "church", with a diminutive ending, says Behind the Name, hedge included, and it belonged to a 7th-century Irish saint who evangelized in Franconia and was martyred in Würzburg. The American record barely existed before this century: about 10 boys in the 1990s, about 210 in the 2000s, about 1,200 in the 2010s, and about 2,700 so far this decade. Its famous contemporary bearer is the Irish actor Cillian Murphy, an Academy Award winner, and Behind the Name carries the Anglicized spelling Killian as its own entry, also used in France, with its own separate American record. An Irish saint who died in Bavaria, a probable church at the root, and a C spelling whose American story arrived in force only this century.
Popularity, 1890–2024
Shape drawn from US Social Security baby-name records. Cillian peaked in the 2020s.
When you meet Cillian
Most people given the name Cillian in the United States are children or teenagers today. The name belongs to this generation.
Estimated from US Social Security birth registrations and typical lifespans; a rough guide, not a rule.
The Cillian deep dive
Whether you’re naming a baby or exploring your own name’s history, this is a personal letter, not a list: where Cillian truly comes from, how it traveled, and what a century of records reveals. If you have grown a tree on nametree, it also considers how Cillian fits with your family’s names and surname.
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