Cotton is a soft fiber that grows around the seeds of the cotton plant (Gossypium sp.), a shrub native to tropical and subtropical regions around the world, including the Americas, India, and Africa. However, virtually all of the commercial cotton grown today worldwide is grown from varieties of the native American species Gossypium hirsutum and Gossypium barbadense. The fiber is most often spun into yarn or thread and used to make a soft, breathable textile, which is the most widely used natural-fiber cloth in clothing today. The English name derives from the Arabic word al qutun, meaning "cotton fiber". (The Spanish word algodón has the same etymology.)
Cotton fiber, once it has been processed to remove seeds and traces of wax, protein, etc., consists of nearly pure cellulose, a natural polymer. Cotton production is very efficient, in the sense that ten percent or less of the weight is lost in subsequent processing to convert the raw cotton bolls (seed cases) into pure fiber. The cellulose is arranged in a way that gives cotton fibers a high degree of strength, durability, and absorbency. Each fiber is made up of twenty to thirty layers of cellulose coiled in a neat series of natural springs. When the cotton boll is opened, the fibers dry into flat, twisted, ribbon-like shapes and become kinked together and interlocked. This interlocked form is ideal for spinning into a fine yarn.
As of 2007, the seven largest producers of cotton in the world are (1) China, (2) India, (3) the United States, (4) Pakistan, (5) Brazil, (6) Uzbekistan and (7) Turkey
Cotton is a water thirsty crop, and as [water resources] get tighter around the world, economies that rely on it face difficulties and conflict, as well as potential environmental problems.