Namewise

Cillian vs Oisin

Cillian and Oisincompared 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.

  • Northern Ireland · Boys

    In 2024, Cillian was ranked #2 and Oisin #9 among boys in Northern Ireland.

  • Republic of Ireland · Boys

    In 2025, Cillian was ranked #9 and Oisin #262 among boys in Republic of Ireland.

  • Scotland · Boys

    In 2024, Cillian was ranked #83 and Oisin #234 among boys in Scotland.

  • England and Wales · Boys

    In 2025, Cillian was ranked #217 and Oisin #517 among boys in England and Wales.

Cillian and Oisin over time

Cillian and Oisin appear together in 3 published lists, across 113 years of shared records. Oisin held the stronger position in more years in 3 of them, Cillian in 0.

The order between them changed and held in 3 of those lists — a change in that published list, never a claim that one name displaced the other.

Oisin reached its own highest recorded position earlier in 3 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.

How this pair is related

The relationship kinds these two qualify for, each under its own stated rule. Every one is drawn from a list they both appear in.

  • One took the other's place near the top

    In Republic of Ireland · Boys, Cillian moved into the top 50 at #17 in 2018 as Oisin fell out of it to #247, having been #11 the year before.

  • One moved ahead of the other

    In 2023, Cillian moved ahead of Oisin in Northern Ireland · Boys — #9 and #7 the year before became #4 and #7.

  • Repeatedly exchanged positions

    Cillian and Oisin changed places 5 times in England and Wales · Boys between 1996 and 2025, ending at #217 and #517.

  • Closest over the longest run

    Across 55 shared years in Republic of Ireland · Boys, Cillian and Oisin averaged 58.7 places apart, ending at #9 and #262.

  • Mirrored each other

    Over 55 shared years in Republic of Ireland · Boys, Cillian rose about as far as Oisin fell — from #305 and #163 in 1970 to #9 and #262 in 2025.

  • Longest-running competitions

    Cillian and Oisin were both ranked in England and Wales · Boys for 30 years, from 1996 to 2025, ending at #217 and #517.

  • Peaked in the same years

    Both reached their highest recorded position in Northern Ireland · Boys within 2 years — Cillian #2 in 2024, Oisin #7 in 2022.

List by list

  • Republic of Ireland · Boys55 shared years, 1970–2025

    Cillian held the stronger position in 9 of those years, Oisin in 46.

    Highest recorded here: Cillian #4 in 2024, Oisin #8 in 2016.

    The order changed in 2018: Cillian moved ahead. In 2017 they stood at #16 and #11; by 2018 that had become #17 and #247.

    Most recent shared year, 2025: Cillian #9, Oisin #262.

  • England and Wales · Boys30 shared years, 1996–2025

    Cillian held the stronger position in 14 of those years, Oisin in 15.

    Highest recorded here: Cillian #177 in 2024, Oisin #433 in 2021.

    The order changed in 2014: Cillian moved ahead. In 2013 they stood at #730 and #692; by 2014 that had become #550 and #616.

    Most recent shared year, 2025: Cillian #217, Oisin #517.

  • Northern Ireland · Boys28 shared years, 1997–2024

    Cillian held the stronger position in 6 of those years, Oisin in 21.

    Highest recorded here: Cillian #2 in 2024, Oisin #7 in 2022.

    The order changed in 2023: Cillian moved ahead. In 2022 they stood at #9 and #7; by 2023 that had become #4 and #7.

    Most recent shared year, 2024: Cillian #2, Oisin #9.

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.

Other comparisons involving Oisin

Pairs where Oisin shares a published list with another name, each measured inside one registrar's own list.

Other pairs with the same kind of relationship

Pairs that qualify under the same rule as this one — one moved ahead of the other.

All one moved ahead of the other→

Other pairs from Northern Ireland lists

Pairs measured inside Northern Ireland's own published lists, where this pair's strongest relationship is also recorded. Positions in these lists are not comparable with another registrar's.

Northern Ireland overview→

Other pairs ranked together in the 2020s

Pairs both ranked in the same published list at some point between 2020 and 2029.

The 2020s across all registrars→

Side by side

Side-by-side comparison of Cillian, Oisin
FieldCillianOisin
Record typeEditorially researched profileEditorially researched profile
Gender usagemalemale
MeaningProbably from Old Irish 'cell' (church) combined with a diminutive suffix.Traditionally interpreted as 'little deer', combining an Old Irish word for deer or stag with a diminutive ending.
OriginIrishIrish
PronunciationNot yet recorded/oʊˈʃiːn/
Syllables22
Common variants / nicknamesNot yet recordedNot yet recorded
Recorded regional usageGB-ENW, GB-NIR, GB-SCT, IEGB-ENW, GB-NIR, GB-SCT, IE
Most recent popularity observationRepublic of Ireland · Boys #9 (2025)Republic of Ireland · Boys #262 (2025)
Pronunciation clarity (demonstration score)Not yet recorded90/100
Spelling simplicity (demonstration score)82/10094/100
International familiarity (demonstration score)100/100100/100
Data Confidencemediummedium

What the data shows

  • Both Cillian and Oisin share a recorded Irish origin.
  • Cillian and Oisin both have 2 syllables.
  • Cillian's recorded meaning differs from Oisin's — see the table above for each.
  • Both names have recorded usage in GB-ENW, GB-NIR, GB-SCT, IE.

How each name got here

Cillian

Popularity journey

  1. 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

  2. Highest recorded1997–2024

    Highest recorded position: #2 among boys in Northern Ireland, in 2024 (recorded 1997–2024).

    Northern Ireland · Boys

  3. Most recent2025

    Most recently recorded at #217 among boys in England and Wales, in 2025.

    England and Wales · Boys

Oisin

Popularity journey

  1. First recorded1964

    First recorded at #232 among boys in Republic of Ireland in 1964 — the earliest year that source publishes this name, not necessarily the earliest it was used.

    Republic of Ireland · Boys

  2. Highest recorded1997–2024

    Highest recorded position: #7 among boys in Northern Ireland, in 2022 (recorded 1997–2024).

    Northern Ireland · Boys

  3. Most recent2025

    Most recently recorded at #517 among boys in England and Wales, in 2025.

    England and Wales · Boys