Texas (English: state of Texas), referred to as Texas, is the largest state in the south of the United States and the second largest state in the United States, second only to Alaska. The name of the state comes from the Caddoan "tejas" of the Indian hasinai people, which means "friend" or "ally". When Spanish explorers named Texas, they mistook it for a place name, so they used it.The West Bay coastal plain area, the northern central plain area, the great plain area, and the Pecos area. One third of southeastern Texas belongs to the West Bay coastal plain; the northern central plain extends from the central part of Texas to the panhandle in the eastern half, which is basically some hills and valleys without trees. The great plain is located to the west of the northern central plain, and is a part of the prairie that extends all the way to Canada. Pecos district is located in the west of Texas. It is a dry area with magnificent scenery and rock.Undiscovered natural gas resources with potential to increase reserves in the Mississippi Barnett shale in the Fort Worth basin, North Central Texas. In the bend dome Fort Worth basin, the definition of Barnett Paleozoic total oil and gas system includes the distribution area of organic rich Barnett shale as the main source rock of Paleozoic carbonate and clastic reservoirs. By the end of 2005, about 3500 vertical wells and 1000 horizontal wells had been completed, of which more than 85% were completed after 1999.Texas basically has a temperate climate, and some parts of the South have a subtropical climate. It is warm in winter and hot in summer. Rainfall varies from place to place, with an average annual rainfall of 666 mm. The area near the sea is humid and the inland is dry. In the East and North, there are heavy rains in summer, and tornadoes in the north from April to June every year. There are many hurricanes in the coastal area of southeast Gulf of Mexico from June to November every year.Known for its energy and petrochemical industries, Texas is the largest energy and chemical state in the United States. Oil and natural gas production accounts for 1 / 3 and 1 / 4 of the U.S. production respectively, and refining capacity accounts for more than 1 / 4 of the U.S. production. Since the 1980s, Texas has carried out the policy of economic diversification. Although oil and natural gas are still the main industries in Texas, their proportion has declined, and high-tech industries have developed rapidly. Houston, San Antonio and Dallas triangle have become the second "Silicon Valley" in the United States, and Houston has developed into the largest medical training and treatment center in the United States and even in the world. Houston, Dallas fortworth, San Antonio Austin corridor and Texas Mexico border are the fastest growing metropolitan areas in the United States.