The Collaborative International Dictionary of English v.0.48:

Exercise \Ex"er*cise\, n. [F. exercice, L. exercitium, from
   exercere, exercitum, to drive on, keep, busy, prob. orig., to
   thrust or drive out of the inclosure; ex out + arcere to shut
   up, inclose. See Ark.]
   1. The act of exercising; a setting in action or practicing;
      employment in the proper mode of activity; exertion;
      application; use; habitual activity; occupation, in
      general; practice.
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            exercise of the important function confided by the
            constitution to the legislature.      --Jefferson.
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            O we will walk this world,
            Yoked in all exercise of noble end.   --Tennyson.
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   2. Exertion for the sake of training or improvement whether
      physical, intellectual, or moral; practice to acquire
      skill, knowledge, virtue, perfectness, grace, etc. "Desire
      of knightly exercise." --Spenser.
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            An exercise of the eyes and memory.   --Locke.
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   3. Bodily exertion for the sake of keeping the organs and
      functions in a healthy state; hygienic activity; as, to
      take exercise on horseback; to exercise on a treadmill or
      in a gym.
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            The wise for cure on exercise depend. --Dryden.
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   4. The performance of an office, a ceremony, or a religious
      duty.
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            Lewis refused even those of the church of England .
            . . the public exercise of their religion.
                                                  --Addison.
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            To draw him from his holy exercise.   --Shak.
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   5. That which is done for the sake of exercising, practicing,
      training, or promoting skill, health, mental, improvement,
      moral discipline, etc.; that which is assigned or
      prescribed for such ends; hence, a disquisition; a lesson;
      a task; as, military or naval exercises; musical
      exercises; an exercise in composition; arithmetic
      exercises.
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            The clumsy exercises of the European tourney.
                                                  --Prescott.
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            He seems to have taken a degree, and performed
            public exercises in Cambridge, in 1565. --Brydges.
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   6. That which gives practice; a trial; a test.
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            Patience is more oft the exercise
            Of saints, the trial of their fortitude. --Milton.
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   Exercise bone (Med.), a deposit of bony matter in the soft
      tissues, produced by pressure or exertion.
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