The full form of GYM is Gymnasium. Gymnasium is a Greek word that means "school for naked exercise" and was used to designate a locality for the education of young men, including physical education (gymnastics, for example, exercise) which was customarily performed naked, as well as bathing, and studies. Today, gymnasiums are commonplace in the United States. They are in virtually all U.S. colleges and high schools, as well as almost all middle schools and elementary schools. These facilities are used for physical education, intramural sports, and school gatherings. The word "gym" is also slang for "fitness center," which is often an area for indoor recreation.