From Mexico, an unleavened, round, flat bread resembling a very thin pancake. Tortillas can be made from corn flour (masa) or wheat flour, but they are always baked on a griddle. Tortillas 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 refrigerated section of most supermarkets. In Spain the word tortilla refers to a thin omelet, the tradition version of which contains potatoes and Spanish onions.