Trepak is a musical term referring to a Russian form of dance song built on a quick duple meter.http://www.music.vt.edu/musicdictionary/textt/Trepak.html The Cossacks were the inventors of this musical form. In most English usage, "Trepak" (capitalized) refers to a short piece from Tchaikovsky's ballet The Nutcracker; it is one of several consecutive ethnic dances in the ballet. It also goes under the name "Russian Dance" (the other ethnic dances of the ballet also have dual names, e.g.