Aceto-dolce is a pickled Italian mixture of fruits and vegetables, used as a relish or as an hors d'oeuvre. It is typically made by pickling produce in vinegar, and then jarring with a syrup of grape must, honey, and mustard.
Note that when Italian recipes call for a measure of "aceto dolce", it is referring instead to a sweet vinegar, such as one blended with a fruit juice, a true Balsamic vinegar, or Japanese mirin.
Name origins
Aceto dolce is Italian, literally "sour-sweet."