Cillian vs Oisín
Cillian and Oisíncompared on official birth-registration statistics and Namewise's recorded data. This page states what each name's record shows — it never picks a winner or scores one name against the other.
Head to head
Ranks are only compared within one published list and one year. Two ranks from different years, from a boys' and a girls' list, or from different registrars are not comparable, so they are not placed side by side.
Republic of Ireland · Boys
In 2025, Cillian was ranked #9 and Oisín #5 among boys in Republic of Ireland.
Cillian and Oisín over time
Cillian and Oisín appear together in 1 published list, across 8 years of shared records. Oisín held the stronger position in more years in 1 of them, Cillian in 0.
In none of those lists did their order change and stay changed.
Oisín reached its own highest recorded position earlier in 1 of those lists, and Cillian in none. Each position is a place inside its own list, so this compares when they peaked and never how high.
Counted list by list. Two names in the same published list are measured on the same scale in the same year, so those comparisons are real — but positions from different lists are not, so nothing here is combined into an overall standing.
List by list
Republic of Ireland · Boys8 shared years, 2018–2025
Cillian held the stronger position in 3 of those years, Oisín in 5.
Highest recorded here: Cillian #4 in 2024, Oisín #5 in 2023.
The order between them never changed and held in this list.
Most recent shared year, 2025: Cillian #9, Oisín #5.
Two names moving past each other in a ranking is a fact about the ranking. Namewise does not claim one name displaced the other, that families chose between them, or that either influenced the other — none of that is in this data.
Where to go next
Comparisons that share a name, a rule or a published list with this one. Each is an existing comparison page with its own evidence — nothing here says these pairs are alike.
Other comparisons involving Cillian
Pairs where Cillian shares a published list with another name, each measured inside one registrar's own list.
- Jason vs Cillian
Over 55 shared years in Republic of Ireland · Boys, Cillian rose about as far as Jason fell — from #53 and #305 in 1970 to #135 and #9 in 2025.
Jason · Cillian · 55 shared years, 1970–2025 · Mirrored each other
- Cillian vs Marcus
Over 55 shared years in Republic of Ireland · Boys, Cillian rose about as far as Marcus fell — from #305 and #111 in 1970 to #9 and #232 in 2025.
Cillian · Marcus · 55 shared years, 1970–2025 · Mirrored each other
- Cillian vs Nicholas
Over 55 shared years in Republic of Ireland · Boys, Cillian rose about as far as Nicholas fell — from #305 and #81 in 1970 to #9 and #198 in 2025.
Cillian · Nicholas · 55 shared years, 1970–2025 · Mirrored each other
- Cillian vs Ronan
Over 55 shared years in Republic of Ireland · Boys, Cillian rose about as far as Ronan fell — from #305 and #54 in 1970 to #9 and #86 in 2025.
Cillian · Ronan · 55 shared years, 1970–2025 · Mirrored each other
Side by side
| Field | Cillian | Oisín |
|---|---|---|
| Record type | Editorially researched profile | Official statistical record (evidence-only) |
| Gender usage | male | male |
| Meaning | Probably from Old Irish 'cell' (church) combined with a diminutive suffix. | Not yet recorded |
| Origin | Irish | Not yet recorded |
| Pronunciation | Not yet recorded | Not yet recorded |
| Syllables | 2 | 1 |
| Common variants / nicknames | Not yet recorded | Not yet recorded |
| Recorded regional usage | GB-ENW, GB-NIR, GB-SCT, IE | IE |
| Most recent popularity observation | Republic of Ireland · Boys #9 (2025) | Republic of Ireland · Boys #5 (2025) |
| Pronunciation clarity (demonstration score) | Not yet recorded | Not yet recorded |
| Spelling simplicity (demonstration score) | 82/100 | 94/100 |
| International familiarity (demonstration score) | 100/100 | 40/100 |
| Data Confidence | medium | medium |
What the data shows
- Cillian has a recorded origin (Irish); Oisín does not have one recorded yet.
- Cillian has 2 syllables, compared with 1 for Oisín.
- A meaning is recorded for Cillian; Oisín doesn't have one written yet.
- Both names have recorded usage in IE.
How each name got here
Cillian
Popularity journey
First recorded1970
First recorded at #305 among boys in Republic of Ireland in 1970 — the earliest year that source publishes this name, not necessarily the earliest it was used.
Republic of Ireland · Boys
Highest recorded1997–2024
Highest recorded position: #2 among boys in Northern Ireland, in 2024 (recorded 1997–2024).
Northern Ireland · Boys
Most recent2025
Most recently recorded at #217 among boys in England and Wales, in 2025.
England and Wales · Boys
Oisín
Popularity journey
First recorded2018
First recorded at #15 among boys in Republic of Ireland in 2018 — the earliest year that source publishes this name, not necessarily the earliest it was used.
Republic of Ireland · Boys
Highest recorded2018–2025
Highest recorded position: #5 among boys in Republic of Ireland, in 2023 (recorded 2018–2025).
Republic of Ireland · Boys
Most recent2025
Most recently recorded at #5 among boys in Republic of Ireland, in 2025.
Republic of Ireland · Boys