Source : Webster's Revised Unabridged Dictionary (1913)

Calisthenics \Cal`is*then"ics\, n.
   The science, art, or practice of healthful exercise of the
   body and limbs, to promote strength and gracefulness; light
   gymnastics.

Source : WordNet®

calisthenics
     n : light exercise designed to promote general fitness [syn: {callisthenics},
          {calisthenic exercise}, {callisthenic exercise}]