The authors agree that this surname has a common base: it derives from terms that designated rural groupings of houses, whether the generic word casale or its dialectal variants. F. De Laurentiis notes that the surname was formed from names, nicknames and gentilics linked to place names such as Casale, Casaletto and Casalino, widely distributed throughout the Italian peninsula, and that these place names designated originally a rural dwelling, a rustic building or a plot of land with a farmhouse.

E. De Stefani documents a variant of Friulian origin, in which the surname derives from the dialectal word cjasâl, equivalent to casale, with which were identified those who lived in a group of houses distant from the main settlement. The cjase and the cjasâl were architectural units characteristic of the rural Carnia, a mountainous area of northern Friuli-Venezia Giulia, in the province of Udine. De Stefani records its presence documented from at least the end of the 17th century in the localities of Pesariis and Pieria, both belonging to Prato Carnico.

V. Blunda provides a Sicilian perspective: the surname comes from the dialectal word casàli, meaning "hamlet" or "small village", and could have originated in a place name applied to the one who came from one of the numerous casali of the territory of Sicily during the late Middle Ages, intermediate nuclei between the isolated farmstead and the village, characteristic of peasant settlement under the Norman-Swabian and Aragonese feudal administration.