The term 'Wine-Producing Region' refers to two specific regions: Napa (4 letters) and Medoc (5 letters). Napa is a wine-producing region located in California, USA, known for its Cabernet Sauvignon and Chardonnay wines. Medoc is a wine-producing region located in Bordeaux, France, known for its red wines such as Cabernet Sauvignon, Merlot, and Cabernet Franc. Both regions are renowned for their high-quality wines.