Head to head · Boys' names
Cillian vs Collin
#507 vs #493 in 2025
Collin is a whisker ahead (#493 vs #507 in 2025), but the curves point different ways: Collin is holding its place on the charts, Cillian is climbing the charts fast. On momentum, Cillian has the edge.
Cast your vote
Which one would you pick?
Your gut first, the numbers after — the split shows once you pick.
The tale of the tape
On the charts, Collin leads 5 measures of 6; Cillian leads 1.
Ranks, counts and years are measured in the official US birth record; the classroom and living figures are estimates computed from it. The dot marks the side each measure favours on the charts — more common, not better.
What the records say
146 years of US births, drawn on one scale
Two curves, one scale
Who owned which decade
- 1890s: Cillian —, Collin #1079 — Collin higher
- 1900s: Cillian —, Collin #1068 — Collin higher
- 1910s: Cillian —, Collin #1837 — Collin higher
- 1920s: Cillian —, Collin #1891 — Collin higher
- 1930s: Cillian —, Collin #1905 — Collin higher
- 1940s: Cillian —, Collin #1143 — Collin higher
- 1950s: Cillian —, Collin #1081 — Collin higher
- 1960s: Cillian —, Collin #850 — Collin higher
- 1970s: Cillian —, Collin #587 — Collin higher
- 1980s: Cillian —, Collin #340 — Collin higher
- 1990s: Cillian #9390, Collin #157 — Collin higher
- 2000s: Cillian #5017, Collin #146 — Collin higher
- 2010s: Cillian #1569, Collin #260 — Collin higher
- 2020s: Cillian #667, Collin #472 — Collin higher
Collin stood higher in every recorded decade — 14 of 14.
Rank by decade
| Decade | Cillian | Collin |
|---|---|---|
| 1890s | — | #1079 |
| 1900s | — | #1068 |
| 1910s | — | #1837 |
| 1920s | — | #1891 |
| 1930s | — | #1905 |
| 1940s | — | #1143 |
| 1950s | — | #1081 |
| 1960s | — | #850 |
| 1970s | — | #587 |
| 1980s | — | #340 |
| 1990s | #9390 | #157 |
| 2000s | #5017 | #146 |
| 2010s | #1569 | #260 |
| 2020s | #667 | #472 |
Average national rank across each decade. A dash means the name sat outside the recorded top of that decade.
Around the world
Cillian
- Scotland#100
Collin
Not charting outside the US.
National statistics offices, latest published year.
The names themselves
Meaning, roots, sound and the people who carried each
Where each name comes from
Cillian
Either 'church' with a small-thing ending, or 'sense, wisdom'
Two serious readings compete. One traces it to Old Irish cell, 'church' or 'monastic cell' (itself borrowed from Latin cella), plus the diminutive -án. The other traces it to Old Irish cíall, 'sense, sanity, wisdom'. Both are defensible on the linguistic evidence and neither has won.
Cillín → Cillian → Killian → Kilian
How it traveled
The name belongs to early Christian Ireland, the era of small stone churches and monks who kept traveling east. The best-documented bearer is the seventh-century Irish missionary Cillian, who preached in Franconia and was martyred at Würzburg around 689; his cult made the name a fixture in Bavaria, where it settled as Kilian and has been in continuous use ever since.
Collin
a young hound, or little Nicholas
Two unrelated lines meet here. The Gaelic Cailean means a whelp or young dog, which was a compliment in a hunting culture rather than an insult. The English Colin is Col, an old short form of Nicholas, with the French diminutive ending -in. Both were in use in Britain by the Middle Ages, and the spelling with two l's usually points to the Gaelic surname.
Cailean → Colin → Collin
How it traveled
Cailean Mòr Caimbeul died in the thirteenth century and gave the Campbell chiefs their Gaelic title, which is why the name is bound so tightly to that clan. Separately, English shepherds in Elizabethan poetry are constantly called Colin, from the French diminutive — the two Colins were already being confused four hundred years ago.
Where a reading is contested the note says so — this page does not turn a guess into a fact. The chain is each name's recorded forms, oldest first; the story is its opening, told in full on the name's own page.
Out loud, and in short
Cillian
KIL-ee-an
The Irish C is always a hard K; there is no 's' sound in it. Three syllables in careful speech, often compressed to two in fast speech (KIL-yan). The stress stays on the first syllable in Irish, English and German alike.
- Cill — The most usual clipped form in Ireland, informal and family-level; rhymes with 'kill', which is worth knowing before you adopt it.
- Cilly — Occasional affectionate extension of Cill, used within families rather than in public.
- Cillian — Most bearers use the full name in every register — three short syllables do not press hard for a nickname.
Collin
KAH-lin
Two syllables, stress on the first. Britain says it that way too, though British Colins with one l often take a longer first vowel — KOH-lin — which is a real transatlantic difference and a source of small confusion.
- Col — The name without its ending, which is the medieval short form of Nicholas; plain and rarely written.
- Cal — A near-substitution rather than a shortening; a standing American name of its own and easier in speech.
Is it right for you
The differences that decide it, laid out by what you want
Choose by what you want
Choose Cillian if you want…
- a name fewer children share#507 in 2025 — cillian will almost certainly be the only one in school
- a name on the way upup 450 places on the charts in five years
- a name with more sound in itCillian runs 3 syllables, Collin 2
- a name that charts abroad tooCillian is on the national lists of Scotland
Choose Collin if you want…
- a name most people already know#493 in 2025, 613 babies that year
- a name holding steadyCollin is holding its place on the charts
- a name with fewer syllablesCollin is 2 syllables to Cillian's 3
Each line is a measured difference between the two names — a rank, a count, a recorded form — never a judgement of either. Save the one that answers your question; it lands on your shortlist.
The trade-offs, name by name
Cillian
Strengths
- One pronunciation across Ireland, Britain, Germany and France — the sound does not shift when the name crosses a border.
- A documented record stretching back to a seventh-century Irish missionary, and continuous use in Bavaria ever since.
- The K-spellings, Killian and Kilian, are already familiar to English speakers, so the name reads as a name on first sight.
To consider
- The C will be read as an S by people who have not met the name: expect 'SILL-ee-an' from receptionists and substitute teachers, and expect to correct it politely for life.
- Cillian, Killian and Kilian all exist and all sound the same. Whichever you choose, the name will usually need spelling out over the phone.
- The obvious short form, Cill, sounds exactly like 'kill'. Most bearers simply use the full name, but it is better to notice this now than in a playground.
Collin
Strengths
- Both possible origins are respectable and old, so there is something real to tell either way.
- It is entirely familiar to every English speaker and needs no explanation.
- Six letters, two syllables, and no difficulty of spelling or saying.
To consider
- Colin with one l is the older and internationally commoner spelling, and mail will use both.
- British and American speakers give the first vowel different lengths, which travelers notice.
- It was very well used in the 1990s, so a man of that age will have met several.
Documented properties of each name — how it spells, travels and shortens — not opinions about the child.
How each is likely to age
Cillian
57%chance Cillian feels dated by 2040
Cillian is climbing fast right now. Steep climbs tend to come with steep descents — the quicker a name arrives, the more firmly it belongs to its moment.
Collin
40%chance Collin feels dated by 2040
Collin sits in the calm middle of the cycle — neither chasing a wave nor sliding off one. Middle-of-the-cycle names age slowly and predictably.
A reading of where each name sits on the long naming cycle — computed, not measured, and explained on the data page.
With your last name
Say both in full. The notes are facts about letters and sound — a rhyme, a shared initial, the monogram — not a verdict on either name.
Type a last name to hear Cillian and Collin in full.
Weighing the whole shortlist? Run the full comparison — up to eight names with your last name, initials, classroom projections and a printable report.
Decide together
Nobody names a baby alone
Still torn between Cillian and Collin?
Put both to the vote.
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More head-to-heads
Same measures, different pair. Sixty more are dealt daily in the arena.
Lists these names appear on
- Scottish gems the US hasn't discovered
- Irish names beyond St. Patrick's Day
- Names ending in -in
- all guides
Where Cillian and Collin each sit in the library — alternatives in the same style, ranked by the same records.
Cillian or Collin — the short answers
- Which is more popular, Cillian or Collin?
- Collin, in 2025: Collin ranked #493 with 613 babies; Cillian ranked #507 with 595 babies.
- Which name is rising faster, Cillian or Collin?
- Cillian. Over the last five years Cillian moved up 450 places; Collin moved down 28 places.
- Which is the older name, Cillian or Collin?
- Cillian entered the US charts in 1995; Collin entered the US charts in 1895. On the American record, Collin is the older name.
- How many people are named Cillian and Collin?
- About 4,100 people named Cillian are estimated to be alive in the US today. About 79,000 people named Collin are estimated to be alive in the US today.
- Will there be other Cillians or Collins in the classroom?
- Cillian will almost certainly be the only one in school. Collin will almost certainly be the only one in school.
US figures from the Social Security Administration, 1880–2025; international figures from national statistics agencies. Votes are battle voters on this site, not the birth record. Data & methodology
Keep playing
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