The authors agree that Cerrato is a surname of probable toponymic origin, linked to the root cerr-, referring to the Turkey oak (Quercus cerris), a variety of oak very widespread in the Italian peninsula. Numerous Italian place names incorporate this root: Cerro, Cerri, Cerreto, Cerrina, among others, which supports the hypothesis that the surname arose in areas characterised by the presence of these trees.

F. De Laurentiis notes that the surname is typical of Tuscany and that a derivation from the regional word cirro or ciro, meaning "lock of hair" or "curl", cannot be entirely ruled out. In that same sense, it is considered that this alternative interpretation —linked to the Latin cirrus— is secondary, and that for Cerrato the arboreal or toponymic interpretation remains the predominant one.

From the geographical point of view, two main historical areas are recorded: one in western Piedmont —with documentation in the Cuneo and Asti areas from the 16th and 17th centuries respectively— and another in the Naples and Salerno area. Presence is also documented in Tuscany. Among the related variants are Cerrati, Cerruti, Ceruti, Cerruto, Cerreto and Cerri, each with its own regional distribution within Italy.