The authors differ as to the origin of this surname. E. Rossoni holds that it would be of Slavic origin, derived from the name of Iska, a district of Zadar in Croatia, or else from the Slovene village of Iska, near Ljubljana. Its presence in Sicily —with pockets in Palermo and in Trapani— he does not find incompatible with this hypothesis.

V. Blunda, by contrast, proposes a Sicilian dialect explanation: the surname would come from the word ìsca, which designates a river islet or a strip of cultivated land beside a riverbed. The term alluded to the fertile ground deposited by the current, prized for its moisture. According to Blunda, the surname may have originated as a microtoponym applied to the inhabitant of those riverside plots, and later became a surname.