E. Rossoni notes that this surname would derive directly, or through dialect alterations, from the Slavic name Ion —the equivalent of Giovanni— or from the name Iona, an archaic form of the biblical name Giona (Jonah). The surname has multiple independent clusters of origin (ceppi), arisen in different regions without direct relation between them. It is documented in Lazio, specifically in Trevi nel Lazio and in the Frosinone area, in Rome and in Cisterna di Latina, in the Latina area; it also appears in the Crotone area, in the municipalities of Rocca di Neto and Belvedere di Spinello.

P. Durante, by contrast, proposes a different etymology: he considers the surname to be of Greek origin and relates it to the term ion, meaning "violet".

Rossoni further records formal variants linked to this same origin. The variant Ionà is proper to Calabria, with a presence in Soveria Simeri, Catanzaro and Lamezia Terme, in the Catanzaro area. The variant Ioni shows specific areas in the Pesaro area —with a presence in Pesaro, Piobbico and Urbania—, in Terni and in Rome. The variant Ione is almost unique and is recorded in southern Italy.