Pima cotton is a kind of cotton with an extra long staple, or fiber length. Pima was developed in the United States via a selective breeding program using Egyptian varieties with extra long fibers.
Pima is a crossbred variety of Gossypium barbadense, a cotton species that naturally has coarse and medium-long fibers. After much research and artificial breeding, the Pima strain was created in the early 1900s. It is named in honor of the Pima, a Native American group that aided the United States Department of Agriculture in developing the cotton at an agricultural facility in Sacaton, Arizona.
Pima's fiber length makes it smoother than cotton with shorter staples. It is also particularly strong and firm. Pima is considered a generic term for the strain, while Supima is a licensed trademark for Pima grown exclusively in the United States.