Cillian
Meaning: not confirmed (origin debated)
About the name Cillian
The origin of Cillian is debated, and we couldn't confirm its meaning from a sourced etymology. A commonly cited theory links it to Irish roots, with the meaning âLittle church; or warâ. Treat that as a theory, not a settled fact.
Why we say this: we only state a meaning as fact when a sourced etymology (Wiktionary, with its references) supports it. For Cillian we didn't find one we were confident in, so we show the popular explanation as a theory.
It has a unique feel. In 2025, Cillian ranked #507 for boys in the US, with 595 babies given the name. Its peak year since 1940 was 2024. Since 2000, 100% of US babies named Cillian were boys.
- US rank 2025
- #507
- In 2015
- #1418
- Babies in 2025
- 595
Popularity of Cillian, 1940â2025
Latest SSA data: 2025.
Popularity data: U.S. Social Security Administration national baby names (public domain; names given to at least 5 babies of one sex per year).
Names similar to Cillian
Name meanings marked or linked âWiktionaryâ are adapted from Wiktionary by Wiktionary contributors, CC BY-SA 4.0; each name page links its source entry.