Cillian

What Cillian means

Irish, possibly meaning “strife”

Irish saint's name, possibly derived from ceallach (“strife”) (ultimately from Proto-Indo-European *kelh₂- (“to beat, strike”)) or ceall (“monastery, church”).

Source: Wiktionary, “Cillian” (revision 79358109), CC BY-SA 4.0. Quoted from the etymology; we don’t write our own.

How popular is Cillian?

US: Rising: up from #1416 in 2015. England & Wales: Rising: up from #404 in 2015.

Biggest US share so far: 2024, when 668 boys got the name (#463 that year). First in the US records in 1995.

How common

• About 1 in 2,871 baby boys in the US in 2025
• About 1 in 1,182 baby boys in England and Wales in 2025
• About 1 in 385 baby boys in Scotland in 2025

“1 in N” divides by all listed births for that sex. The US list leaves out names given to fewer than 5 babies, and the UK lists leave out names given to 2 or fewer, so the real figure is a little rarer than shown.

Where in the US

Most popular in AK (2.2 per 1,000 boys), DE (1.7 per 1,000 boys), RI (1.6 per 1,000 boys) in 2025.

SSA state data, 2025. Share of all listed boys born in each state.

US vs UK

Cillian is #507 in the US and #217 in England & Wales (2025).

Same sex as this page (boys). SSA (US), ONS (England and Wales), NRS (Scotland).

Boy or girl?

In 2025, 99.9+% of US babies named Cillian were boys.

Counts below the publishing threshold (US 5, UK 3) are not included.

Other spellings

Other spellings parents chose in 2025

• Zillion7 US

Names that sound the same and differ by a letter or two, with baby counts for the same sex. US and E&W counts.

If you like Cillian

Boys

• Emerson#254Editor’s note Up from #300 in 2015 to #254 in 2025 in the US
• Santiago#26Spanish form of James, meaning “May He Heel”^*
• Charlie#145Editor’s note More popular in England & Wales than the US: #22 vs #145 in 2025
• Ace#164Editor’s note Climbing fast in the US: #419 in 2015, #164 in 2025
• Asher#28Editor’s note More popular in the US than England & Wales: #28 vs #150 in 2025
• Kash#286Editor’s note Up from #382 in 2015 to #286 in 2025 in the US

For a sister

• Luciana#273Editor’s note More popular in the US than England & Wales: #273 vs #1,809 in 2025
• Evangeline#147“good news”^*
• Evie#270Editor’s note Up from #510 in 2015 to #270 in 2025 in the US
• Violet#13From the word “violet”^*
• Liliana#78Form of Lilian, possibly meaning “lily”^*
• Ruby#64Editor’s note Up from #83 in 2015 to #64 in 2025 in the US. About 1 in 450 US girls in the 2025 records

Picked from the US top 1,000 in 2025: names Wiktionary also files under where there are enough, topped up with common names whose US popularity since 1990 rose and fell most like Cillian’s. Place names are only included if they are in the top 300. Rank is US 2025.