Kiernan
An Irish surname usually taken as a form of MacKiernan, meaning “son of Kieran/Ciarán.”
The #5,802 most common surname in the United States (2010 Census) — about 1 in every 51,751 Americans shares it.
Etymology
Kiernan is generally treated as an anglicized form of an Irish surname built on the personal name Ciarán (later Kieran). That name comes from ciar, meaning “dark” or “black,” with the diminutive ending -án, so the original sense is “little dark one.” In the historical sources, Kiernan is grouped with MacKernan, Kernan, Kernon, and related Irish forms, reflecting the same underlying Gaelic personal name.
History
The name appears in Irish records in several spellings, especially Kiernan, Kernan, Kernon, and MacKernan. It is most strongly associated with Ireland, particularly the Gaelic surname tradition of surnames formed from a father’s or ancestor’s personal name. The saint’s name Ciarán also helped keep the form familiar and widespread in Irish usage.
Origin
Regions
Variant spellings
Fun fact
The same Gaelic root behind Kiernan also gave English the given name Kieran, now common well beyond Ireland.
From the historical record
“a p.n. Kiernan. From the Irish Kerna- ghan ; a p.n. Kightly. See Keightley Kilbourn. From Kilburn ; a loc. n., Middlx.”
— British Family Names: their origin and meaning (2nd ed.)