Quahog - The Native American name for the (East Coast) hard-shelled clam. Quahog is also sometimes used to describe very large clams.

Quesadilla - A flour tortilla filled, folded, then cooked. The filling usually contains shredded cheese, but may also include ground meat, refried beans, etc.. Recipe: Baked Ham and Cheese Quesadillas

Queso - The Spanish word for cheese.
Recipe: Hot Chile Con Queso

Quiche - This dish is a pastry crust filled with a savory egg custard which usually includes cheese, seasonings, vegetables, and other ingredients. It's typically baked in a shallow, straight-sided, fluted baking dish.
Recipe: Quiche Lorraine

Quick Bread - Quick bread is made with baking soda or baking powder, which is why it's called "quick."
Recipe: Butter Pecan Bread

Quinoa - Quinoa is a protein rich grain which is also high in unsaturated fat and lower in carbohydrates than most grains. It may be used in any dish in place of rice or similar grains.
Recipe: Tomato-Basil Bread