The Collaborative International Dictionary of English v.0.48:

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

   Syn: calisthenics, calisthenic exercise, callisthenic
        exercise.
        [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

calisthenics
    n 1: the practice of calisthenic exercises; "calisthenics is
         recommended for general good health" [syn: calisthenics,
         callisthenics]
    2: light exercises designed to promote general fitness; "several
       different calisthenics were illustrated in the video" [syn:
       calisthenics, callisthenics]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "calisthenics":
   athletics, breather, constitutional, daily dozen, drill,
   eurythmics, exercise, exercising, gymnastic exercises, gymnastics,
   isometrics, physical culture, physical education, physical jerks,
   practice, setting-up exercises, stretch, workout, yoga