Fionna is a variant of Fiona, from Gaelic roots meaning "fair" or "white."
Fionna is a Celtic given name rooted in the Old Irish and Scottish Gaelic adjective fionn, meaning "fair," "bright," or "blessed" — a word that in early Irish literature described both physical fairness (light hair, pale complexion) and a quality of luminous moral goodness. The most famous bearer of the root is Fionn mac Cumhaill, the legendary Irish hero whose name means simply "the fair one" and whose cycle of stories — the Fenian Cycle — represents one of the great bodies of early medieval Irish literature. Fionn gained his extraordinary wisdom by accidentally tasting the Salmon of Knowledge, and his band of warriors, the Fianna, gave their name to Irish republicanism's most enduring political tradition.
The explicitly feminine form Fiona was popularized in the nineteenth century by the Scottish writer William Sharp, who published symbolist poetry and prose under the pseudonym Fiona Macleod — a choice that both feminized the root and gave the name a literary, Celtic Revival atmosphere it has never entirely shed. Fionna, with the doubled n, represents a spelling variant that emphasizes the Gaelic orthographic tradition and distinguishes the name from the Shrek association that has followed Fiona since 2001, giving parents a way to access the same linguistic roots with a slightly different visual identity. Fionna combines genuine antiquity with contemporary freshness.
It sounds entirely modern to ears unaware of the Fenian legends, yet it carries within it one of the oldest living naming traditions in Europe. The name works across cultures — accessible to anglophone speakers, recognizable to those with Irish or Scottish heritage, and poetic enough to stand on its own merits wherever it travels.