Likely a variant of Arianna, the Italian form of Ariadne, a Greek name meaning most holy.
Arianni is a lyrical variant of the Ariana/Arianna family, names with deep roots in both classical antiquity and ancient geography. The Greek Ariadne — meaning "most holy" or "utterly pure" — was the Cretan princess who gave Theseus the thread that led him out of the Labyrinth, making her name synonymous with guidance through darkness and impossible courage. Separately, "Ariana" derives from the ancient Persian and Avestan concept of the Aryan homeland, a geographical term that once described the region encompassing modern Iran and Afghanistan.
The Italian form Arianna gained enormous popularity in the Baroque period through opera: Claudio Monteverdi's Lamento d'Arianna (1608) is one of the earliest surviving operatic works, and her mournful aria became so famous that copies circulated across Europe. The name carried that air of passionate, poetic tragedy into the Romantic era and beyond. Arianni — with its doubled consonant and Italian-inflected ending — reads as an even more musical, ornate variant that began surfacing in American birth records in the early 2000s.
It suggests the influence of both Italian-American naming traditions and a broader appetite for names that feel romantic and elaborate. The name occupies a sweet spot between the ancient and the fashionable, evoking myth, music, and Mediterranean warmth all at once.