E. De Felice notes that this surname derives from the given name Mercurio, fairly widespread in the Middle Ages thanks to the cult of several saints who bore it. This name continues the Latin nomen Mercurius, taken from the god of commerce, protector of inventors and messengers. From the etymological point of view, it was linked by popular etymology with the Latin terms merx mercis ("merchandise") and mercari ("to trade"), although De Felice considers an Etruscan origin probable.

P. Durante, by contrast, proposes a Greek origin from a personal name, without offering further precision.