F. De Laurentiis maintains that this surname has as its base a matronymic derived from the feminine name Diana. That name can refer both to the goddess of the moon, the forests and the hunt of Roman mythology, and to the common term diana —always derived from the name of the goddess— which, with Christianity and during the Middle Ages, adopted in several regions of Italy the meaning of "sorceress, witch" or also of "fairy".

V. Blunda proposes, on the other hand, an etymology of Sicilian and dialectal origin, without relation to the feminine proper name. According to this author, the surname comes from the dialectal word dianu, which designated the quantity of arable land in a single day of work, a unit equivalent to the Italian term giornata or to the Latin iugerum of Roman law. This measure varied according to the quality of the terrain and was used to quantify parcels in rustic lease contracts in Sicily. As a surname, Blunda suggests that it could have originated in the trade of the surveyor or in some minor place name linked to a parcel of extension known by that measure.

Both proposals are incompatible with each other, which suggests that the surname presents independent clusters of origin (ceppi) arisen in different regions without direct relation.