A taco is a traditional Mexican dish composed of a corn or wheat tortilla folded or rolled around a filling. A taco can be made with a variety of fillings, including beef, pork, chicken, seafood, vegetables, and cheese, allowing for great versatility and variety. A taco is generally eaten without utensils and is often accompanied by garnishes such as salsa, chili pepper, avocado, guacamole, cilantro (coriander), tomatoes, onions, and lettuce.
The origins of the taco are not precisely known, and etymologies for the culinary usage of the word are generally theoretical.
According to one etymological theory, the culinary meaning of "taco" derives from its "plug" meaning as employed among Mexican silver miners, who used explosive charges in plug form consisting of a paper wrapper and gunpowder filling.
Indigenous origins for the culinary word "taco" are also proposed. One possibility is that the word derives from the Nahuatl word "tlahco", meaning "half" or "in the middle," in the sense that food would be placed in the middle of a tortilla. Furthermore, dishes analogous to the taco were known to have existed in Pre-Columbian society—for example, the Náhuatl word "tlaxcalli" (a type of corn tortilla).
According to wikipedia