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.
      [1913 Webster]

            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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The Collaborative International Dictionary of English v.0.48:

Exercise \Ex"er*cise\, v. t. [imp. & p. p. Exercised; p. pr. &
   vb. n. Exercising.]
   1. To set in action; to cause to act, move, or make exertion;
      to give employment to; to put in action habitually or
      constantly; to school or train; to exert repeatedly; to
      busy.
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            Herein do I Exercise myself, to have always a
            conscience void of offence.           --Acts xxiv.
                                                  16.
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   2. To exert for the sake of training or improvement; to
      practice in order to develop; hence, also, to improve by
      practice; to discipline, and to use or to for the purpose
      of training; as, to exercise arms; to exercise one's self
      in music; to exercise troops.
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            About him exercised heroic games
            The unarmed youth.                    --Milton.
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   3. To occupy the attention and effort of; to task; to tax,
      especially in a painful or vexatious manner; harass; to
      vex; to worry or make anxious; to affect; to discipline;
      as, exercised with pain.
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            Where pain of unextinguishable fire
            Must exercise us without hope of end. --Milton.
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   4. To put in practice; to carry out in action; to perform the
      duties of; to use; to employ; to practice; as, to exercise
      authority; to exercise an office.
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            I am the Lord which exercise loving-kindness,
            judgment, and righteousness in the earth. --Jer. ix.
                                                  24.
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            The people of the land have used oppression and
            exercised robbery.                    --Ezek. xxii.
                                                  29.
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The Collaborative International Dictionary of English v.0.48:

Exercise \Ex"er*cise\, v. i.
   To exercise one's self, as under military training; to drill;
   to take exercise; to use action or exertion; to practice
   gymnastics; as, to exercise for health or amusement.
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         I wear my trusty sword,
         When I do exercise.                      --Cowper.
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WordNet (r) 3.0 (2006):

exercise
    n 1: the activity of exerting your muscles in various ways to
         keep fit; "the doctor recommended regular exercise"; "he
         did some exercising"; "the physical exertion required by
         his work kept him fit" [syn: exercise, exercising,
         physical exercise, physical exertion, workout]
    2: the act of using; "he warned against the use of narcotic
       drugs"; "skilled in the utilization of computers" [syn:
       use, usage, utilization, utilisation, employment,
       exercise]
    3: systematic training by multiple repetitions; "practice makes
       perfect" [syn: exercise, practice, drill, practice
       session, recitation]
    4: a task performed or problem solved in order to develop skill
       or understanding; "you must work the examples at the end of
       each chapter in the textbook" [syn: exercise, example]
    5: (usually plural) a ceremony that involves processions and
       speeches; "academic exercises"
    v 1: put to use; "exert one's power or influence" [syn: exert,
         exercise]
    2: carry out or practice; as of jobs and professions; "practice
       law" [syn: practice, practise, exercise, do]
    3: give a workout to; "Some parents exercise their infants"; "My
       personal trainer works me hard"; "work one's muscles"; "this
       puzzle will exercise your mind" [syn: exercise, work,
       work out]
    4: do physical exercise; "She works out in the gym every day"
       [syn: exercise, work out]
    5: learn by repetition; "We drilled French verbs every day";
       "Pianists practice scales" [syn: drill, exercise,
       practice, practise]

Moby Thesaurus II by Grady Ward, 1.0:

398 Moby Thesaurus words for "exercise":
   Nachtmusik, abrade, absolute music, absorb, absorb the attention,
   act, acting, action, active use, activism, activity, adaptation,
   aerobics, agency, aggravate, agitate, air varie, aleatory,
   aleatory music, annoy, appliance, application, apply, apprentice,
   apprenticeship, arrangement, arrest, assignment, athletics,
   baccalaureate service, badger, bait, basic training, be at,
   bedevil, behavior, beset, bestow, boning, bother, brainwork, break,
   break in, breaking, breather, breed, breeding, bring to bear,
   bring up, bristle, brown off, bug, bullyrag, burden, burn up,
   busywork, calisthenics, callisthenics, carry on, catch,
   celebration, ceremonial, ceremony, chafe, chalk talk,
   chamber music, chamber orchestra, chare, charge, charm, chivy,
   chore, commencement, commission, composition, concern, condition,
   conditioning, conduct, conning, constitutional, consumption,
   contemplation, convocation, cram, cramming, cultivate, cultivation,
   daily dozen, descant, develop, development, devil, direction,
   discharge, discipline, discompose, discourse, disquisition,
   distemper, distress, disturb, do, do with, dog, doing, drill,
   drilling, driving, duty, effect, electronic music, employ,
   employment, empty formality, enchant, engage, engage in,
   engage the attention, engage the mind, engage the thoughts,
   engross, engross the mind, engross the thoughts, engrossment,
   enthrall, errand, etude, exasperate, execute, execution, exercises,
   exercising, exert, exertion, exploit, exposition, extensive study,
   fascinate, fash, fetch up, fetching-up, fish to fry, fit, fix,
   follow, form, formal, formality, foster, fostering, fret, function,
   functioning, gall, get, go in for, good use, grab, graduation,
   graduation exercises, grind, grinding, grip, gripe, groom,
   grooming, gymnastic exercises, gymnastics, handle, handling,
   harangue, harass, hard usage, hard use, harmonization, harry,
   headwork, heckle, hector, hold, hold spellbound, hold the interest,
   homework, homily, hound, house-train, housebreak, housebreaking,
   hypnotize, ill use, immerse, improve, improvement,
   in-service training, inaugural, inauguration, incidental music,
   initiation, inspection, instruction, instrumental music, invention,
   involve, involve the interest, irk, irritate, isometrics, job,
   job of work, labor, lecture, lecture-demonstration, lesson,
   lick into shape, limber up, liturgy, lucubration, make use of,
   make-work, manage, management, manipulate, manipulation,
   manual training, matters in hand, mental labor, mesmerize, miff,
   military training, mission, misuse, molest, monopolize, moral,
   moral lesson, morality, moralization, movement, movements, mummery,
   nag, needle, nettle, nocturne, nudzh, nurse, nurture, nurturing,
   object lesson, observance, obsess, occupation, occupy,
   occupy the attention, odd job, office, on-the-job training,
   operancy, operate, operation, operations, opus, orchestration,
   peeve, performance, performing, persecute, perturb, perusal,
   pester, physical education, physical jerks, pick on, piece,
   piece of work, pique, plague, play, pluck the beard, ply, pother,
   practice, praxis, preachment, preoccupy, preparation, prepare,
   production, program music, project, prosecute, provoke, pursue,
   put forth, put in tune, put into practice, put out, put to school,
   put to use, raise, raising, reading, ready, readying, rear,
   rearing, recital, recitation, rehearsal, rehearse,
   religious ceremony, responsibility, restudy, restudying, review,
   ricercar, ride, rile, rite, rite de passage, rite of passage,
   ritual, roil, rough usage, ruffle, running, score, send to school,
   sermon, service, set, set task, setting-up exercises,
   skull session, sloyd, solemnity, solemnization, sonata, sonatina,
   specialize in, spellbind, steering, stint, stretch,
   string orchestra, string quartet, study, studying, subject, swing,
   swotting, tackle, take in hand, take on, take to, take up, talk,
   task, teaching, tease, theme and variations, things to do, throw,
   torment, train, training, trio, trouble, try, try the patience,
   tweak the nose, undertake, upbringing, usage, use, using up,
   utilization, utilize, variation, vex, vocational education,
   vocational training, wage, warm up, warm-up, wide reading, wield,
   work, work at, work out, working, working-out, workings, workout,
   worry, wrong use, yoga