Meaning and name origin
Kiernan \ki(er)-nan\ as a boy's name is of Irish and Gaelic origin, and the meaning of Kiernan is "black". Kiernan is a variant of Kieran (Irish, Gaelic): name of a saint (sixth century) who was admired for his generosity. A birth name for boys which is seldom used.
Kiernan has 1 variant form: Kernan.
Kiernan is not a popular first name for males but a very popular surname or last name for all people (#8048 out of 88799, Top 9%) (Source: 2000 U.S. Population Census).
Displayed below is a comparison of the popularity of the boy name Kiernan and its variant forms. The only popular variation form ranked in the Top 1000/100 is Kieran (#576). (Source: 2014 Birth Name Statistics).