Dance is the art of movement of the body, usually rhythmically and to music, using prescribed or improvised steps and gestures. “A dance” is any one prescribed sequence of such movements, or the music to which it is performed, or an event at which it takes place. Dance may also be regarded as a form of nonverbal communication recognisable in other animals; in bee dances and behaviour patterns such as mating dances. Dance can be categorized and described in various ways. It may be analysed purely by its choreography, its repertoire of movements, or it may be classified according to its time or place of origin. Yet study reveals many generic similarities in many different times and places. An important distinction is to be drawn between theatrical and participatory dance. Nevertheless, these two categories are not completely separate. Each may borrow from the other. Social dancers may become professional or competitive dancers, may be watched by millions. Both may also have special functions; they may be ceremonial dances performed only at one time of year, they may be intended as an erotic dance, a war dance or a sacred or liturgical dance. Such dances allow both emotional expression and invocation. Martial arts kata are often compared to dances, and sports such as gymnastics, figure skating and synchronized swimming are generally thought to incorporate dance.