Pronounced Neh-bee-oh-low. A grape varietal, used in the production of red wine, originating in the Piedmont region of Italy. Also grown in the United States and South America. Considered a supreme grape in the Piedmont region of Italy. The Nebbiolo varietal is a blending agent in wines such as Barolo, Barbaresco, and Gattinara. Nebbiolo is the Italian word for fog.