Pas means “step,” and deux means “two.” Hence pas de deux, a dance for two. The term can be applied to a duet, but it most often suggests a traditional ballet form in which a man and woman first dance an adagio, then each has a solo, and then they return together for a coda. In classical dance, the tonal possibilities of a pas de deux are endless, and this program at American Contemporary Ballet expresses that range. It presents two works by George Balanchine—his lovely Sonatine (1975) and the Manhattan-brash Rubies (from 1967’s Jewels)—and a new ballet by company director Lincoln Jones, to the music of Mozart. The program concludes with Balanchine’s magnificent final movement from Episodes (1959), set to Anton von Webern’s arrangement of the Ricercata in Six Voices from J. S. Bach’s Musical Offering. The ballet has a corps of 14 women who frame a central couple. The last time I saw it, I was transfixed. —Laura Jacobs