The Collaborative International Dictionary of English v.0.48:

Control \Con*trol"\, n. [F. contr[^o]le a counter register,
   contr. fr. contr-r[^o]le; contre (L. contra) + r[^o]le roll,
   catalogue. See Counter and Roll, and cf. Counterroll.]
   1. A duplicate book, register, or account, kept to correct or
      check another account or register; a counter register.
      [Obs.] --Johnson.
      [1913 Webster]

   2. That which serves to check, restrain, or hinder;
      restraint. "Speak without control." --Dryden.
      [1913 Webster]

   3. Power or authority to check or restrain; restraining or
      regulating influence; superintendence; government; as,
      children should be under parental control.
      [1913 Webster]

            The House of Commons should exercise a control over
            all the departments of the executive administration.
                                                  --Macaulay.
      [1913 Webster]

   4. (Mach.) The complete apparatus used to control a mechanism
      or machine in operation, as a flying machine in flight;
      specifically (A["e]ronautics), the mechanism controlling
      the rudders and ailerons.
      [Webster 1913 Suppl.]

   5. (Climatology) Any of the physical factors determining the
      climate of any particular place, as latitude,distribution
      of land and water, altitude, exposure, prevailing winds,
      permanent high- or low-barometric-pressure areas, ocean
      currents, mountain barriers, soil, and vegetation.
      [Webster 1913 Suppl.]

   6. (Technology) in research, an object or subject used in an
      experimental procedure, which is treated identically to
      the primary subject of the experiment, except for the
      omission of the specific treatment or conditions whose
      effect is being investigated. If the control is a group of
      living organisms, as is common in medical research, it is
      called the

   control group.

   Note: For most experimental procedures, the results are not
         considered valid and reliable unless a proper control
         experiment is performed. There are various types of
         control used in experimental science, and often several
         groups of subjects serve as controls, being subjected
         to different variations of the experimental procedure,
         or controlling for several variables being tested. When
         the effects caused by an experimental treatment are not
         consistent and obvious, statistical analysis of the
         results is typically used to determine if there are any
         significant differences between the effects of
         different experimental conditions.
         [PJC]

   7. (Technology) the part of an experimental procedure in
      which the controls[6] are subjected to the experimental
      conditions.
      [PJC]

   8. the group of technical specialists exercising control by
      remote communications over a distant operation, such as a
      space flight; as, the American Mission Control for manned
      flights is located in Houston.
      [PJC]

   Board of control. See under Board.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Control \Con*trol"\, v. t. [imp. & p. p. Controlled; p. pr. &
   vb. n. Controlling.] [F. contr[^o]ler, fr. contr[^o]le.]
   [Formerly written comptrol and controul.]
   1. To check by a counter register or duplicate account; to
      prove by counter statements; to confute. [Obs.]
      [1913 Webster]

            This report was controlled to be false. --Fuller.
      [1913 Webster]

   2. To exercise restraining or governing influence over; to
      check; to counteract; to restrain; to regulate; to govern;
      to overpower.
      [1913 Webster]

            Give me a staff of honor for mine age,
            But not a scepter to control the world. --Shak.
      [1913 Webster]

            I feel my virtue struggling in my soul:
            But stronger passion does its power control.
                                                  --Dryden.

   3. to assure the validity of an experimental procedure by
      using a control[7].
      [PJC]

   Syn: To restrain; rule; govern; manage; guide; regulate;
        hinder; direct; check; curb; counteract; subdue.
        [1913 Webster]

WordNet (r) 3.0 (2006):

control
    n 1: power to direct or determine; "under control"
    2: a relation of constraint of one entity (thing or person or
       group) by another; "measures for the control of disease";
       "they instituted controls over drinking on campus"
    3: (physiology) regulation or maintenance of a function or
       action or reflex etc; "the timing and control of his
       movements were unimpaired"; "he had lost control of his
       sphincters"
    4: a standard against which other conditions can be compared in
       a scientific experiment; "the control condition was
       inappropriate for the conclusions he wished to draw" [syn:
       control condition, control]
    5: the activity of managing or exerting control over something;
       "the control of the mob by the police was admirable"
    6: the state that exists when one person or group has power over
       another; "her apparent dominance of her husband was really
       her attempt to make him pay attention to her" [syn:
       dominance, ascendance, ascendence, ascendancy,
       ascendency, control]
    7: discipline in personal and social activities; "he was a model
       of polite restraint"; "she never lost control of herself"
       [syn: restraint, control] [ant: unrestraint]
    8: great skillfulness and knowledge of some subject or activity;
       "a good command of French" [syn: command, control,
       mastery]
    9: a mechanism that controls the operation of a machine; "the
       speed controller on his turntable was not working properly";
       "I turned the controls over to her" [syn: control,
       controller]
    10: a spiritual agency that is assumed to assist the medium
        during a seance
    11: the economic policy of controlling or limiting or curbing
        prices or wages etc.; "they wanted to repeal all the
        legislation that imposed economic controls"
    v 1: exercise authoritative control or power over; "control the
         budget"; "Command the military forces" [syn: control,
         command]
    2: lessen the intensity of; temper; hold in restraint; hold or
       keep within limits; "moderate your alcohol intake"; "hold
       your tongue"; "hold your temper"; "control your anger" [syn:
       control, hold in, hold, contain, check, curb,
       moderate]
    3: handle and cause to function; "do not operate machinery after
       imbibing alcohol"; "control the lever" [syn: operate,
       control]
    4: control (others or oneself) or influence skillfully, usually
       to one's advantage; "She manipulates her boss"; "She is a
       very controlling mother and doesn't let her children grow
       up"; "The teacher knew how to keep the class in line"; "she
       keeps in line" [syn: manipulate, keep in line, control]
    5: check or regulate (a scientific experiment) by conducting a
       parallel experiment or comparing with another standard; "Are
       you controlling for the temperature?" [syn: control,
       verify]
    6: verify by using a duplicate register for comparison; "control
       an account"
    7: be careful or certain to do something; make certain of
       something; "He verified that the valves were closed"; "See
       that the curtains are closed"; "control the quality of the
       product" [syn: see, check, insure, see to it,
       ensure, control, ascertain, assure]
    8: have a firm understanding or knowledge of; be on top of; "Do
       you control these data?" [syn: master, control]

Moby Thesaurus II by Grady Ward, 1.0:

551 Moby Thesaurus words for "control":
   Masan, R and D, abate, ability, abnegation, absolutism, abstinence,
   acme, action, address, adeptness, administration, adroitness,
   airmanship, allay, alleviate, ancestral spirits, angel, aplomb,
   apparition, appearance, arrest, arrestation, artfulness,
   artisanship, artistry, ascendancy, assuage, astral, astral spirit,
   attemper, attendant godling, authority, authorization,
   automatic control, bank the fire, banshee, barnstorm,
   be responsible for, be-all and end-all, blue ribbon, blunt,
   bond service, bondage, bravura, bridle, brilliance, button,
   call the shots, call the signals, calm, calmness, capability,
   capacity, captain, captivity, carry authority, carry on,
   cascade control, championship, charge, charisma, charm, chasten,
   check, claws, cleverness, clout, clutches, collect, command,
   competence, composure, conduct, consequence, conservatism,
   constrain, constraint, contain, continence, control action,
   control experiment, controlled experiment, cool, cool off, cooling,
   cooling down, cooling off, coordination, copilot, crack the whip,
   craft, craftsmanship, credit, cunning, curb, curtail, curtailment,
   cut and try, daemon, damp, dampen, de-emphasize, deaden,
   debt slavery, decelerate, deceleration, decide, deftness, demon,
   departed spirit, deprivation of freedom, determine, device,
   dexterity, dexterousness, dextrousness, dial, diminish, diplomacy,
   direct, direction, directorship, discipline, disembodied spirit,
   disenfranchisement, disfranchisement, dispassion, dispose,
   disposition, dominance, dominate, domination, dominion, dompt,
   downplay, drive, dull, duppy, dybbuk, effect, effectiveness,
   efficiency, eidolon, electronic control, eminence, empery, empire,
   empiricism, enchantment, engineer, enjoin, enslavement,
   enthrallment, esteem, evenness, experiment, experimental design,
   experimental method, experimental proof, experimentalism,
   experimentation, expertise, extenuate, facility, fairy godmother,
   familiar, familiar spirit, favor, feedback control, feudalism,
   feudality, finesse, first place, first prize, fly, force, form,
   genius, genius domus, genius loci, gentleness, ghost, golden mean,
   good angel, good feeling, good genius, govern, governance,
   government, grace, grasp, grateful dead, grip, gripe, guard,
   guardian, guardian angel, guardian spirit, guidance, guide, hand,
   handiness, handle, handling, hands, hant, happy medium, haunt,
   have clout, have control of, have in hand, have power,
   have the power, have the right, have the say, have under control,
   head, head up, headship, hegemony, height, helm, helotism, helotry,
   highest, hinder, hindrance, hit and miss, hold, hold at bay,
   hold back, hold fast, hold in, hold in check, hold in hand,
   hold in leash, hold the helm, hold the reins, hold up,
   horsemanship, household gods, husbandry, idolum, immateriality,
   impartiality, imperium, importance, incidental power, incorporeal,
   incorporeal being, incorporeity, indentureship, independence,
   influence, influentiality, ingeniousness, ingenuity, inhibit,
   inhibition, injunction, insinuation, interdict, invisible helper,
   iron hand, judiciousness, jurisdiction, juste-milieu, keep,
   keep back, keep from, keep in, keep in check, keep under control,
   keep within bounds, kingship, knob, know-how, lares and penates,
   lares compitales, lares familiaris, lares permarini,
   lares praestites, lares viales, larva, lay, lay under restraint,
   lead, lead on, leadership, leading, legal restraint, lemures,
   lenify, lenity, lessen, lever, leverage, lighten, lordship,
   magnetism, make the rules, manage, management, managery, managing,
   manes, maneuver, manipulate, manipulation, marksmanship, master,
   mastermind, mastership, mastery, materialization, maximum,
   mechanism, meden agan, middle way, might, mildness,
   ministering angel, mitigate, moderate, moderateness, moderation,
   moderationism, modulate, moment, monopoly, most, ne plus ultra,
   neutrality, new high, noble experiment, nonviolence,
   nothing in excess, numen, obtund, officer, oni, order, ordering,
   oversee, oversight, pacifism, palliate, palms, paramountcy,
   peel off, penates, peonage, personality, persuasion, phantom,
   pilot, pilotage, play down, poltergeist, possess authority,
   possession, potency, power, practical ability, pragmatism,
   predominance, preponderance, prescribe, presence, presidency,
   pressure, prestige, primacy, proficiency, prohibit, prohibition,
   protection, protectionism, protective tariff, prowess, prudence,
   pull, pull in, pull the strings, purchase, put down, quarterback,
   quickness, raj, rationing, readiness, record, reduce,
   reduce the temperature, regnancy, regulate, regulation, reign,
   rein, rein in, reins of government, repose, repress, repute,
   research and development, resource, resourcefulness, restrain,
   restraint, restraint of trade, retard, retardation, retrench,
   retrenchment, revenant, robot control, rule, rule of thumb, run,
   running, savoir-faire, savvy, say, seamanship, self-abnegation,
   self-command, self-conquest, self-control, self-denial,
   self-discipline, self-government, self-mastery, self-possession,
   self-restraint, serenity, serfdom, serfhood, servility, servitude,
   servo control, set back, shade, shadow, shape, shrouded spirit,
   skill, skillfulness, skipper, slacken, slavery, slow down,
   slowing down, smother, snub, sober, sober down, sobriety, soften,
   solo, sovereignty, special providence, specter, spectral ghost,
   spirit, spook, sprite, stability, steadiness, steer, steerage,
   steering, stifle, straiten, strings, style, suasion, subdue,
   subjection, subjugation, subtle influence, suggestion, supervise,
   supervision, supervisory control, suppress, supremacy, sway,
   switch, tact, tactfulness, take command, take in hand,
   take the lead, talons, tame, tariff wall, technical brilliance,
   technical mastery, technical skill, technique, temper, temperance,
   temperateness, tentative method, tentativeness, testing, the conn,
   the helm, the wheel, theophany, thought control, thrall, thralldom,
   timing, tone down, top spot, totem, tranquillity, trial,
   trial and error, trying, tune down, tutelar god, tutelary, tyranny,
   underplay, unexcessiveness, unextravagance, unextremeness,
   unsubstantiality, upper hand, vassalage, via media, villenage,
   virtuosity, vision, walking dead man, wandering soul, weaken,
   wear the pants, weight, whip hand, wield authority, wit, withhold,
   wizardry, workmanship, wraith, zenith, zombie



The Free On-line Dictionary of Computing (30 December 2018):

control
ctrl

   1.  A control key on a keyboard used to
   input control characters.

   2.  A component in a
   graphical user interface, e.g. an Active-X control.