The original Tex-Mex hybrid began with a mixture of European Spanish and the Native-American cookways of the region. When a number of families from the Canary Islands migrated to San Antonio in 1731, they brought a taste for Spanish and North African spices like cumin and cilantro that would differ from those that would become popular in metropolitan Mexico. Some theorists believe that Tex-Mex chili is a descendant of the Moroccan stews that are still today slow-cooked in the distinctive tangine clay oven (others give the dish more of a cowboy origin).

Tex-Mex is spicy, based on chiles, onion, garlic, cumin, cilantro, cayenne and black peppers. Beans are a primary starch, along with the flatbread, wheat or corn based, known as tortillas. The corn chip, the tortilla chip, and the piquant tomato dip known as salsa are all Tex-Mex inventions, better known in bars and casual restaurants in Minneapolis, Seattle, or Chicago than they are in Mexico City or Guadalajara. Some other typical Tex-Mex favorites include:

• Chili: particularly what is also known as chile con carne or Texas chili, a stew of chunked (not ground) beef, onions, garlic, spices and ground dried hot chile peppers. Subject to many varieties throughout the United States.
• Nachos: a favorite American finger food, in its simplest form tortilla chips, covered with chopped jalapeño peppers and melted cheese. Ingredient combinations are unlimited.
• Fajitas: strips of beef, chicken or shrimp stir-fried with onions, tomatoes, and green bell peppers, often served on a sizzling cast-iron platter, with flour tortillas, guacamole, pico de gallo, refried beans, shredded cheese and sour cream.
• Chile con queso: a creamy dip of yellow cheese, diced tomatoes and peppers, sometimes with added meat flavorings. Served warm with tortilla chips.
• Chimichangas: a squat deep-fried filled soft wheat tortilla. Many stories are extant about how the Chimichanga came to be named; the usual consensus is that the word is based on a euphemism for a swear word uttered when the original chef accidentally dropped a burrito into a deep fryer. A crispy, delicious treat.
• Quesadillas: a pan or oven-fried filled wheat tortilla, usually containing cheese combined with other tasty ingredients. Frequently cut into wedges for serving.
  Enchiladas: a stuffed tortilla, wheat but more authentically corn, usually served in the United States bathed in a red chile sauce and melted cheese.
• Guacamole: a thick dip designed to be scooped up with tortilla chips, made of a base of mashed avocado, typically with addition of lemon or lime juice, chopped onion, cilantro, and some kind of chile spicing.
• Burritos: meaning literally “little burro,” the burrito is a soft flour tortilla, often oversized, filled with meats, cheese, beans or a combination of ingredients.
• Refried Beans: Mashed beans, not really “refried;” the term is a misinterpretation of the Mexican Spanish “frijoles refritos” signifying that the beans have been fried thoroughly. Few Tex-Mex dishes are ever served without this staple.
• Salsa: A combination of chiles, tomatoes, onions and spices, sometimes served free with tortilla chips as a starter course or with drinks. Available in many strengths in jars at American supermarkets.
• Pico de Gallo: Literally “rooster’s beak” in Spanish, a condiment made from diced tomatoes, onions and chiles.
• Tacos: a hard-fried corn tortilla bent to form a U-shape and filled with ground meat, refried beans, lettuce, shredded cheese and other toppings. Taco-shells are available at many American supermarkets. A Gordita is a thicker squatter variety of taco.
• Flautas: “flute” in Spanish, these are small, filled cylindrical rolled up tortillas that have been deep fried until crisp.
• Chalupas: a crispy edible bowl creating by deep frying a corn-based masa dough; filled with meats, cheese, sour cream, onions, or clili. Standard dinner restaurants in the United States sometimes use the chalupa as the basis for what they erroneously call a “taco salad.”
• Tamales: a cylindrical cake formed from mashed corn, filled with flakes of beef or pork, steamed in a tied corn husk (the husks are sold separately for this purpose). Frequently served in the United States covered in red sauce and melted cheese.

From Life in the USA a complete web guide to American life for immigrants