E. Rossoni notes that the surname derives from the Latin nomen Cassius, belonging to the gens Cassia. He also proposes a second interpretation, following the scholar Rohlfs, which derives it from the Sicilian term càssia, meaning "acacia". Its presence is characteristic of the Syracuse area, with high frequency also in Catania.

V. Blunda classifies it as a Sicilian surname of dialectal origin, belonging to the group of phytonymic surnames —that is, derived from names of plants—. He develops in greater detail the hypothesis of the dialectal word càssia: the surname could have originated in a microtoponym applied to the one who lived near a notable acacia that served as a local reference, or in the trade of the gatherer of its flowers, traditionally used in perfumery and popular cosmetics. Blunda highlights that the acacia is an ornamental and honey-producing species widely spread in the Sicilian agricultural landscape, especially on the boundaries and paths of the great estates.