The authors agree that this surname is characteristic of Sardinia and derives from the term marra, which in Latin designates the hoe. E. De Felice specifies that its presence is especially notable in the Campidano and the Sassari area, and proposes that the surname may have arisen as a deverbal nickname from marrari ("to hoe") or, more probably, from the noun marra; he further notes that in Logudorese the plural marras takes on the figurative sense of "large, protruding or gapped incisor teeth". De Felice also mentions the infrequent variant Marra, which could go back to the old hypocoristic Marra, a shortened form of Margherita.

E. Rossoni stresses that the surname is distributed fairly evenly across the whole island. He further supplies historical documentation: in the Condaghe di Santa Maria di Bonarcado —a medieval Sardinian register— eleven bearers of the surname appear, and mention is made of Giovanni Marras, bishop of the diocese of Usellus-Ales between 1234 and 1237, who acted as a witness in an important deed between the Holy See, the Kingdom of Arborea and the Sardinian church.