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Kiernan

♀ Girl

Pronounced KEER-nun /ˈkɪər.nən/Medium

Meaning: Kiernan is an Anglicized form of the Irish surname O Ciarnain, 'descendant of Ciarnan', a diminutive of ciar, 'dark; black' — so 'little dark one'. It is used as a given name for both sexes, but leans strongly to boys in the U.S., which we note.Low

In 30 seconds: An Irish surname with depth: Kiernan means 'little dark one', from ciar, 'dark' (said 'KEER-nun'). Usually a boy's name — we note the lean.

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Origin MediumIrish

MeaningKiernan is an Anglicized form of the Irish surname O Ciarnain, 'descendant of Ciarnan', a diminutive of ciar, 'dark; black' — so 'little dark one'. It is used as a given name for both sexes, but leans strongly to boys in the U.S., which we note.

U.S. rank (2024)#14367 ↘ Falling

2024 U.S. births6 girls (0.00% of U.S. girls)

Peak year2002

Total births (all-time)≈ 678

Popularity in the U.S. · SSA data

U.S. births per year (Social Security Administration, 1880–present). Pink marker = peak year.

SSA data updated May 2026. How we source & verify this data.

History & Origin

Kiernan is an Anglicization of the Irish surname O Ciarnain, 'descendant of Ciarnan'. Ciarnan is a double diminutive of ciar, 'dark; black', so the sense is 'little dark one'. The surname is long established in Ireland, and, like many Irish surnames, it crossed into given-name use in America. Used here for a girl, it is more often a boy's name — the lean is clear and we note it plainly (said 'KEER-nun').

For girls it appears only rarely in the U.S., against heavier use for boys. Rare for girls, Irish, and strong.

Did you know? The Irish word ciar means 'dark' — it gives Ciaran, Ciara and, through the surname O Ciarnain, Kiernan: 'little dark one'. Kiernan leans strongly to boys, which we note (said 'KEER-nun').

Overall data confidence 55%

References — Kiernan — Irish surname O Ciarnain; ciar 'dark'; boy-leaning in U.S. use

Variations

KernanCiarnanKiernon

Nicknames

KierKikiNan

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If you like Kiernan…

Ciara— shares the Irish root ciar, 'dark'

Keira— a like Irish-rooted name for girls

Kerrigan— a like Irish surname name

Keagan— another Irish name

Regan— another Irish name

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Frequently Asked

What does the name Kiernan mean?

Kiernan comes from the Irish surname O Ciarnain, from ciar, 'dark' — 'little dark one'.

How do you pronounce Kiernan?

It's said KEER-nun /ˈkɪər.nən/ — two syllables, stress on the first.

Is Kiernan a boy or girl name?

Kiernan is used for both, but it leans strongly to boys in the U.S. — a lean we note plainly.

How popular is Kiernan?

Kiernan is rare for girls in the U.S., and more often given to boys.