boy name · Irish origin
Cillian
/ KIL-ee-un /
Meaning
Cillian means Bright-headed; church (Irish).
Gender
Boy
Origin
Irish
Pronunciation
KIL-ee-un
Popularity
#507 · U.S. boys (2025)
Popularity of Cillian in the US, 1880–2025
Cillian first appears in US records in 1995. It peaked in 2024, when 668 boys were given the name; in 2025 there were 595.
Source: US Social Security Administration.
What does Cillian mean?
Cillian is linked to “bright-headed” and to cill, “church” or “monastery.”
Frequently asked questions
What does the name Cillian mean?
Cillian means Bright-headed; church. Cillian is linked to “bright-headed” and to cill, “church” or “monastery.”
What is the origin of the name Cillian?
Cillian is of Irish origin.
How do you pronounce Cillian?
Cillian is pronounced “KIL-ee-un.”
Is Cillian a boy or a girl name?
Cillian is most commonly used as a boy name.
How popular is the name Cillian?
In 2025, Cillian ranked #507 among boys’ names in the United States, according to U.S. Social Security Administration data.
When was the name Cillian most popular?
Cillian was most popular in 2024, when about 668 US babies were given the name that year, according to US Social Security Administration records.