1. Mexico's everyday bread, the unleavened tortilla is round and flat it resembles a very thin pancake. The hand-shaped tortilla can be made from corn flour (masa) or wheat flour, but is always baked on a griddle (comal). It can be eaten plain or wrapped around various fillings. Tortillas are the base for burritos, tacos and a multitude of other dishes. Both corn and flour tortillas are sold prepackaged in the refrigerator section of most supermarkets. 2. In Spain, the word tortilla refers to a thin omelet, the traditional version of which contains potatoes and Spanish onions. Other ingredients that may be used include ham, chorizo and peppers.