There are several ways to divide ballroom dance styles and to give you an idea, we will also describe the type of costume the female partner wears:

International Standard: Danced to mostly Western (European type) music. The dancers remain “in frame”, or in an standard embrace throughout the dance. This style of dance includes the waltz, Viennese waltz, tango, quickstep, and slow foxtrot.

The female partner wears a long, full and elaborate gown to emphasize the smooth and graceful movements of the dances. The shoe is a specialized “closed’ shoe (closed toe box).

International Latin dance is most often danced to Latin American music. This style includes the cha-cha, samba, rumba, paso doble, and jive. In these dances, the female dancer usually wears a short dress which reveals the long leg lines. The shoe is a specialized latin high-heeled sandal.

American Smooth: also often danced to Western music, and like the International Standard, includes the waltz, tango, foxtrot, and Viennese waltz. The difference is that in this style, the partners can separate for open turns, dips, and footwork. The female partner usually wears a longer and flowing gown to emphasize the more dramatic movements across the floor. The shoe is a ‘Smooth’ shoe which is a bit more open on the sides than the International Standard shoe and allows more freedom of foot movement.

American Rhythm: is similar to International Latin and is also danced to rhythmic Latin American music. This style includes the cha-cha, bolero, mambo, rumba, and East Coast swing. As with International Latin, the female dancer wears a short dress and most often the latin sandal, but that can vary with the dance.

As you can see, there is a lot of overlap between the styles, International vs American, however in competition, the styles and entries are clearly delineated.