Pregliato, together with its graphic variant Pregliatto, is a rare Italian surname, not documented as an autonomous entry in the classic onomastic repertoires consulted.

The structure of the surname suggests a link with the better-documented Pregliasco, recorded in genealogical repertoires with around 356 bearers and characteristic of the north-western Italian area, especially the territory of Ovada (province of Alessandria, Piedmont) and the zone bordering Liguria.

Possible origin and formation:

• The most probable etymology links it with a microtoponym (the name of a small or local place) not documented in standard repertoires.
• This microtoponym would be located in the Alessandria-Ligurian area.

Evolution and dialectal variants:

• The suffix -asco, typical of the Ligurian-Piedmontese sphere and of Celto-Ligurian origin, usually has the value of "belonging to" or "originating from."
• The suffix -ato / -atto, frequent in Venetan and eastern Piedmontese areas, may have a diminutive or provenance value.
• This difference suggests that Pregliato would be an alternative regional form of Pregliasco, with the same base origin but adapted to different dialectal contexts.

Distribution:

• The presence of the surname is very reduced.
• It does not figure as an autonomous entry in the classic Italian onomastic repertoires.

In sum, Pregliato / Pregliatto seems to derive from a toponymic origin shared with Pregliasco, reinterpreted through dialectal variations of northern Italy, especially between the Ligurian and Piedmontese spheres.