Source : Webster's Revised Unabridged Dictionary (1913)

Tango \Tan"go\, n.; pl. {Tangos}. [Sp., a certain dance.]
   (a) A difficult dance in two-four time characterized by
       graceful posturing, frequent pointing positions, and a
       great variety of steps, including the cross step and
       turning steps. The dance is of Spanish origin, and is
       believed to have been in its original form a part of the
       fandango.
   (b) Any of various popular forms derived from this.