Prosecco is an Italian white wine - generally a Dry or Extra Dry sparkling wine — normally made from Glera (“Prosecco”) grapes. DOC prosecco is produced in the regions of Veneto and Friuli Venezia Giulia in Italy, and traditionally mainly in the areas near Conegliano and Valdobbiadene, in the hills north of Treviso.

Prosecco is mainly produced as a sparkling wine in either the fully sparkling (spumante) or lightly sparkling (frizzante, gentile) varieties. Prosecco spumante, which has undergone a full secondary fermentation, is the more expensive variant. The sparkling variants may contain some Pinot bianco or Pinot grigio wine. Depending on their sweetness, in accordance with the EU Sweetness of wine Regulations for Terms used to indicate sweetness of sparkling wine, Proseccos are labelled “Brut” (up to 12 grams per litre of residual sugar), “Extra Dry” (12–17 g/l) or “Dry” (17–32 g/l). A still wine (calmo or tranquillo) is also made from Glera grapes – it amounts to only about five percent of production – but this wine is rarely exported. Wines from the traditional Conegliano–Valdobbiadene production area are labeled as “Prosecco di Conegliano-Valdobbiadene”, “Prosecco di Conegliano” or “Prosecco di Valdobbiadene” or “Prosecco DOC” from Friuli. Proseccos labeled with another, non-protected designation, such as “IGT-Veneto”, are generally cheaper and of a more varied quality.

(from: wikipedia)