According to the linguist Gerhard Rohlfs, the surname Arca is of Greek-Byzantine origin and is documented in the province of Reggio Calabria, especially in Polistena. He relates it to the Greek cognomen Arkàs, interpreted as "maker of arks or chests", in reference to a craft trade. The surname constitutes a testimony of the Byzantine linguistic and cultural influence in southern Italy.

Other interpretations agree in linking the surname with craft activities. E. Rossoni derives it from the Sardinian term arca ("large chest" or "wooden box"), suggesting that it originally identified a carpenter or maker of chests. More secondarily, it could also have alluded to the economic prosperity of the family or to the supposed avarice attributed to the founding ancestor.

The surname is documented in Sardinia from the Middle Ages. Among the signatories of the Peace of Eleonora of 1388 appear numerous people surnamed de Arca. Among the most notable historical figures is Arca Proto (Bitti, 1562–1599), a Jesuit priest and historian, author of a work on the revolt of Leonardo Alagón.

For his part, V. Blunda proposes an alternative Greek etymology, deriving it from arclàs, a term that would designate a "maker of bows" for hunting or war. According to this interpretation, the surname would have arisen as a trade nickname later transmitted along the family line.

Finally, P. Durante suggests a relation with the Greek arkhè, a word meaning "beginning", "origin" or "leadership", although this hypothesis has less documentary support.

In migration records and documents of the Americas it is frequent to find the simplified form Arca, without diacritics or graphic variants of origin.