A taco ( /ˈtɑːkoʊ/) 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, 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, avocado or guacamole, cilantro, tomatoes, onions and lettuce.
According to the Real Academia Española, publisher of Diccionario de la Lengua Española, the word taco describes a typical Mexican dish of a maize tortilla folded around food (“Tortilla de maíz enrollada con algún alimento dentro, típica de México“). The original sense of the word is of a “plug” or “wad” used to fill a hole (“Pedazo de madera, metal u otra materia, corto y grueso, que se encaja en algún hueco”). The Online Etymological Dictionary defines taco as a “tortilla filled with spiced meat” and describes its etymology as derived from Mexican Spanish, “light lunch,” literally, “plug, wadding.”
The taco predates the arrival of Europeans in Mexico. There is anthropological evidence that the indigenous people living in the lake region of the Valley of Mexico traditionally ate tacos filled with small fish. Writing at the time of the Spanish conquistadors, Bernal Díaz del Castillo documented the first taco feast enjoyed by Europeans, a meal which Hernán Cortés arranged for his captains in Coyoacán. It is not clear why the Spanish used their word, “taco”, to describe this indigenous food.
~ from Wikipedia
“Although the term taco comes from a Spanish word meaning “light snack”, the taco itself had its origins in pre-Hispanic times, when the Aztecs and other groups in their empire, using corn tortillas much as Europeans used bread, rolled the tortillas or broke them into pieces to scoop up food. The food being scooped was, of course, different in each region and the street taco as we know it today evolved from the rural areas of Mexico.”
~ from Ask.com