Is "Prosecco" a grape or a region?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
Prosecco is not a wine grape but an appellation, right? What does this mean?
—Pam, India
Dear Pam,
That's correct: Prosecco is a sparkling wine designation from the Veneto and Friuli-Venezia Giulia regions of northeastern Italy. It's popular for being both food-friendly and wallet-friendly.
Some wines are called by the name of the grape they are made from (such as Chardonnay), while others are named for the region they hail from (Champagne comes from the Champagne region of France). Appellations are officially defined winegrowing areas; while the rules vary by country, in Europe, an appellation often requires certain grapes or winemaking techniques to be used. So to say “Champagne,” is to refer to both the particular area, but also to a wine that is made from a specific grape or blend in that area by a specific method.
In the case of Prosecco, it’s a bit more confusing. Prosecco is both a geographic designation and the former name of the region's primary grape variety, which is now called Glera. In 2009, Italy officially switched the name of the grape to try to protect the wine's region of origin and prevent "Prosecco" from being made all over the world. Prosecco is now a DOC, or Denominazione di Origine Controllata, a category in the Italian system for defining wine regions and wine names. The Prosecco DOC production zone, which includes the village of Prosecco, is large, spanning nine provinces! Within that area, Italy also recognizes a more specific "superior" Prosecco terroir with the stricter Prosecco Superiore DOCG in the hilly production areas of Conegliano-Valdobbiadene and Colli Asolani.
Under the DOC rules, Prosecco wines can be a blend of Glera with up to 15 percent of other varieties such as Chardonnay, Pinot Bianco, Pinot Grigio or some less-familiar native grapes. It's a lot to think about when you're just trying to kick back with a fresh summer sipper!
—Dr. Vinny