Noah Boy
NOH-uh
“rest, comfort” · Hebrew
#2
Cillian
BoyIrish· “uncertain; possibly church or strife”
- Meaning
- uncertain; possibly church or strife (origin disputed)
- Origin
- Irish
- Pronunciation
- KIH-lee-uhn
- Syllables
- 2
- US rank 2025
- #507
- US babies 2025
- 595
- Best rank
- #463 (2024)
- Peak year
- 2024
Meaning and origin of Cillian
Cillian is often said to mean “uncertain; possibly church or strife”; the origin is uncertain, though it is usually linked to Irish roots.
Cillian is an Irish name of uncertain meaning. It is often linked to cill, "church," giving the sense "little church," or to ceallach, sometimes glossed as "strife," but scholars do not agree. Saint Cillian, also spelled Kilian, was an Irish missionary who traveled to Franconia and was martyred at Würzburg, where he is still honored. The name has been used in Ireland for centuries and has gained international attention through Irish actor Cillian Murphy. Pronounced KIH-lee-uhn, it has a soft, lyrical sound. Cillian offers an authentic Irish choice with deep roots, though its spelling can puzzle some English speakers.
Popularity over time
Cillian first appears in US Social Security records in 1995. It has ranked in the top 1,000 in 6 different years, starting in 2020. Its best national rank was #463 in 2024, the same year it reached its highest count of 668 babies. In 2025, 595 babies were named Cillian, and it ranked #507 nationally. That is 392% more than ten years earlier, so it is clearly on the rise.
Its national rank moved from #2,359 in 2010 and #507 in 2025. Of the 4,084 US boys named Cillian since records began, 65% were born in the 2020s, its biggest decade. The 2010s come next, with 1,204 babies.
Other boys' names that peaked around the same time include Lucian, Soren, Ayaan, Atreus, and Zaire.
Where it is most popular (2025)
In 2025, Cillian ranked highest in Alaska, Rhode Island, and Delaware.
| State | Rank there | Babies |
|---|---|---|
| Alaska | #169 | 5 |
| Rhode Island | #206 | 5 |
| Delaware | #214 | 5 |
| New Hampshire | #240 | 5 |
| New Mexico | #276 | 7 |
Gender, sound and spelling
In the US it is used almost only for boys.
Cillian is usually pronounced KIH-lee-uhn, with two syllables. It has seven letters, starts with C and ends in “-an”.
Middle names for Cillian
A few middle names that flow with Cillian: each avoids a matching first letter, a rhyme and a vowel clash where the names meet.
Sibling names for Cillian
Similar names
Aidan Boy
AY-dihn
“little fire” · Irish
#326
Ronan Boy
ROH-nuhn
“little seal” · Irish
#247
Killian Boy
KIHL-ee-uhn
“possibly 'little church'” · Irish
#418
Kieran Boy
KEER-uhn
“little dark one” · Irish
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Finnian Boy
FIN-ee-uhn
“fair, white” · Irish
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Ciaran Boy
KEER-uhn
“little dark one” · Irish
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Declan Boy
DEHK-luhn
“uncertain; often said full of goodness” · Irish
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Keegan Boy
KEE-gun
“son of Aodhagán” · Irish
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Brendan Boy
BREHN-duhn
“prince” · Irish
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Kian Boy
KEE-uhn
“ancient, enduring” · Irish
#401
Callan Boy
KA-luhn
“uncertain; from an Irish or Scottish surname” · Irish
#190
Lucian Boy
LOO-shuhn
“light” · Latin
#462
Lists that include Cillian
Frequently asked questions
What does the name Cillian mean?
Cillian is often said to mean “uncertain; possibly church or strife”; the origin is uncertain, though it is usually linked to Irish roots.
What is the origin of the name Cillian?
Cillian has Irish roots. Cillian is an Irish name of uncertain meaning.
Is Cillian a popular name?
Yes. Cillian ranked #507 in the US in 2025, which makes it in the top 1,000.
Is Cillian a boy or girl name?
Cillian is mainly a boy's name. In the US it is used almost only for boys.
How do you pronounce Cillian?
Cillian is usually pronounced KIH-lee-uhn. Stressed syllables are in capital letters.
Popularity figures come from US Social Security card applications (names given to at least five babies in a year, 1880 to 2025). How we source names and meanings