In Italian, whenever you see “un cucchiaio di aceto dolce” (1 teaspoon of aceto dolce), what is meant is “sweet vinegar.” This can be a fruit vinegar — say, Raspberry Vinegar — or even Balsamic Vinegar. Italians would regard the Japanese wine vinegar, “Mirin”, as “aceto dolce.”
Otherwise Aceto Dolce refers to a pickled mixture of fruits or vegetables — what we might refer to in English as “sweet and sour pickle.”
The fruit or veggies are first pickled in vinegar, then preserved in a syrup made from honey, mustard and either grape must, muscatel wine or white wine.
Aceto Dolce pickle can be served as starters or crudités on a relish plate.
You can buy Aceto Dolce pickled mixtures in bottles.
“Aceto” means “vinegar” in Italian; “dolce” means “sweet”.