E. De Felice notes that this surname is peculiar to southern Sardinia, where it is very frequent, and that it derives from the place name Cabras, the name of a centre in the province of Oristano and of other localities where there were goat farms. He points out that the word for "goat" in Sardinian is kabhra, with the plural kabhras.

E. Rossoni broadens this information and specifies that Cabras is a coastal locality of the western coast of Sardinia, near Oristano, inhabited since the 5th millennium BC. As for the etymology, he notes that both the place name and its Sardinian variants craba and crabu refer to the Latin capra ("goat") and caper ("billy goat"). Rossoni also documents the surname in medieval Sardinian sources, among them the Peace of Eleonora of 1388 and the Condaghi of the 11th to 13th centuries.