The authors differ on the origin of the surname. E. Rossoni derives it from the Gothic name Bato, Batonis, and recalls two historical chieftains who bore that name: Bato of the Daesitiates and Bato of the Breuci, both leaders who in the time of Augustus fought in Pannonia against the general Tiberius. Rossoni places the surname mainly in Tuscany: the Florence area —with presence in Florence itself and in Pelago— and the Prato area.

V. Blunda, on the other hand, proposes a different origin for the Sicilian form of the surname: he derives it from the Greek ábbas, "abbot", an ecclesiastical title of Byzantine tradition preserved in the onomastics of Sicily, especially under the forms Abba and Abbate. According to Blunda, Bati would represent a contraction of that same etymon, transformed through family transmission.

The surname therefore presents independent origins in different regions of Italy: a Tuscan stock linked to Germanic anthroponymy, and a Sicilian one tied to the ecclesiastical vocabulary of Greek influence.