In general the term, ballroom dance applies to any one of the several dances in which two individuals, a 'leader' and a 'follower', dance with physical contact through their upper or lower bodies, or simply their arms depending on the particular variety of dance.

In one common usage "ballroom dance" refers to the ten dances of International Standard and International Latin, though the term is also often used interchangeably with the five International Standard dances [5] In the United States, the American Style (American Smooth and American Rhythm) also exists.
Ballroom dances commonly include:
International Style:
International Standard (modern ballroom): Slow Waltz - Tango - Viennese Waltz - Slow Foxtrot - Quickstep
International Latin: Cha Cha - Samba - Rumba - Paso Doble - Jive
American Style:
American Smooth: Waltz - Tango - Foxtrot - Viennese Waltz
American Rhythm: Cha Cha - Rumba - East Coast Swing - Bolero - Mambo
Historical/Vintage Dance: Waltz - Polka - Schottische - Tango - One-Step - Foxtrot
There are other dances as well which are occasionally categorized as ball room dance:
Nightclub: Nightclub Two-step - Hustle - Modern Jive / LeRoc / Ceroc
The whole swing variety: West Coast Swing / East Coast Swing / Carolina Shag / Collegiate Shag
Latin nightclub: Salsa - Merengue - Cumbia - Bachata - Cha cha -Samba
Brazilian Dances: Forró - Pagode - Samba - Lambada
Country/Western: Polka - Cha-cha-cha - Two-step - Waltz
Cajun dance: Cajun One Step or Cajun Jig - Cajun Two Step - Zydeco - Cajun Waltz - Cajun Jitterbug
Other: Argentine tango - Peabody - Cabaret.
And it's not just doing what is learned. Dance is an art and need to be presented with beauty. It should give pleasure not just to the audience but the dancers as well.
And not to forget the judges.
One of the most important aspects of any dance is posture which makes the dance look elegant and exude confidence. The line and hold of the individuals as well as the melding of the body weights of both into one are quite important so that the leading and following appear quite effortless and the dancers are in synchronization with each other.
In addition to these, timing is one of the key aspects of dancing. Basic characterization of a dance to a particular music being played and the choreographic adherence to the musical phrasing and accents are two foremost important aspects in any dance; no amount of proficiency in other aspects can overcome deficiency of these. No need to mention the effect a ball dance can have when the lead and follow appear effortless.
Among the other things are the floor craft, their neatness of appearance, costuming, flow of choreography and basically whether they look like dancers. Last but not least is the presentation of the dance. The elegance, the confidence, the enthusiasm and the pleasure of dancing and expression, can put the stage on fire.
Photo Credit: kevhickey
