The authors agree that this surname derives from a nickname and occupational name originating in the term mezzadro, that is, the settler who worked a piece of land under a sharecropping arrangement —a system by which the worker and the owner shared the produce of the land in equal parts. Both place its diffusion mainly in northern Italy.

E. De Felice specifies that the form Mezzari is proper to Veneto, while Mezzadroli corresponds to Emilia-Romagna, which suggests that the surname shows regional variants arisen from one and the same lexical origin.