E. Rossoni notes that Merighi is typical of the region of Emilia-Romagna, with an area of presence also in the lower Trentino-Alto Adige. According to Rossoni, the surname would derive from the reduced form of the name Amerigo, although he also considers it possible that it comes from the medieval term merigus, which designated the elder of the village.

F. De Laurentiis specifies that the base of the surname is the shortened hypocoristic Merigo, derived from the personal name Amerigo. This name comes from the old Germanic Haimirich, interpreted as "lord of the homeland": haimi ("house, homeland") and rik ("rich, powerful"). De Laurentiis adds that this form was adapted into Italian first as Amerigo and then, in an equivalent way, as Arrigo and Enrico.