The term 'TAS' in tango refers to the role of the tanguero, or leader, in a traditional Argentine tango dance. The tanguero is responsible for leading the couple through the steps and movements of the dance, as well as providing the musical accompaniment. The tanguero is also responsible for setting the pace and direction of the dance, and for ensuring that the couple follows the correct steps and patterns. The tanguero is the one who sets the tone and atmosphere of the dance, and is the one who ultimately determines the success of the performance.