Stato da Mar = Stato dal Mare = State from Sea, State from Oversea (overseas territories)

per analogia di "lo Stato da Terra" (State from Land) a "lo Stato da Mar (territori d’oltremare)

Contesto
strutture dello stato sia in città che nel territorio di terraferma (lo Stato da Terra) che nei territori d’oltremare (lo Stato da Mar)

In 2017 UNESCO inscribed the "Venetian defensive walls built between the 16th and 17th centuries" among the World Heritage Sites. It is not a single structure, but six different defensive walls built by the Serenissima in Italy, Croatia and Montenegro to defend the borders of the Republic of Venice , its ports and its trades.
Between the 16th and 17th centuries, the Republic of Venice started the construction of new fortifications for the defence of the "State from Land" .
https://www.lombardiafacile.regione.lombardia.it/wps/portal/...

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Note added at 24 mins (2022-10-22 15:28:17 GMT)
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The Stato da Màr or Domini da Mar (lit. 'State of the Sea' or 'Domains of the Sea') was the name given to the Republic of Venice's maritime and overseas possessions from around 1000 to 1797, including at various times parts of what are now Istria, Dalmatia, Montenegro, Albania, Greece and notably the Ionian Islands, Peloponnese, Crete, Cyclades, Euboea, as well as Cyprus.
It was one of the three subdivisions of the Republic of Venice's possessions, the other two being the Dogado, i.e. Venice proper, and the Domini di Terraferma in northern Italy.
The overseas possessions, particularly islands such as Corfu, Crete and Cyprus, played a critical role in Venice's commercial and military leadership. In his landmark study on the Mediterranean world in the 16th century, historian Fernand Braudel described these islands as "Venice's motionless fleet".

literal

Stato da Mar, Domini da Mar = 'State of the Sea', 'Domains of the Sea