Variant of Shannon (Irish, "old river") or Shana (Hebrew, "beautiful").
Shanna is a phonetic Americanization of Shannon, itself an anglicization of the Irish Sionainn — the ancient name for Ireland's longest and most celebrated river. The river's name is steeped in Celtic legend, most commonly traced to a mythic figure named Sionann who drowned in a sacred well of wisdom, giving her name to the waters. Linguists also connect the root to a Proto-Celtic word for "old" or "wise," lending the name a quiet, ageless dignity beneath its breezy sound.
Shanna blossomed as a distinct spelling in mid-twentieth-century America, particularly popular through the 1970s and 1980s. It carried the warm, informal energy of the era's naming trends — familiar enough to feel friendly, just distinctive enough to stand apart from plain Shannon. The name found a pop culture boost through Shanna the She-Devil, Marvel Comics' jungle adventurer who debuted in 1972, giving the name a bold, adventurous edge in the imaginations of a generation of readers.
Today Shanna occupies a quietly nostalgic place in naming history — immediately recognizable to those who grew up in its peak decades, yet rare enough among younger generations to feel genuinely individual. Its Irish river roots keep it grounded in something ancient and elemental: the flow of water, the transmission of wisdom, the persistence of landscape through myth.