1. [n]  the activity of managing or exerting control over something; "the control of the mob by the police was admirable"
2. [n]  (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"
3. [n]  a mechanism that controls the operation of a machine; "the speed control on his turntable was not working properly"; "I turned the controls over to her"
4. [n]  discipline in personal and social activities; "he was a model of polite restraint"; "she never lost control of herself"
5. [n]  power to direct or determine; "under control"
6. [n]  great skillfulness and knowledge of some subject or activity; "a good command of French"
7. [n]  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"
8. [n]  the economic policy of controlling or limiting or curbing prices or wages etc.; "they wanted to repeal all the legislation that imposed economic controls"
9. [n]  a spiritual agency that is assumed to assist the medium during a seance
10. [n]  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"
11. [n]  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"
12. [v]  have a firm understanding or knowledge of; be on top of; "Do you control these data?"
13. [v]  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"
14. [v]  verify by using a duplicate register for comparison; "control an account"
15. [v]  handle and cause to function; "do not operate machinery after imbibing alcohol"; "control the lever"
16. [v]  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"
17. [v]  exercise authoritative control or power over; "control the budget"; "Command the military forces"
18. [v]  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"
19. [v]  verify or regulate by conducting a parallel experiment or comparing with another standard, of scientific experiments; "Are you controlling for the temperature?"

1. \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.
   2. That which serves to check, restrain, or hinder;
      restraint. ``Speak without control.'' --Dryden.
   3. Power or authority to check or restrain; restraining or
      regulating influence; superintendence; government; as,
      children should be under parental control.
            The House of Commons should exercise a control over
            all the departments of the executive administration.
                                                  --Macaulay.
   {Board of control}. See under {Board}.
   

2. \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.]
            This report was controlled to be false. --Fuller.
   2. To exercise restraining or governing influence over; to
      check; to counteract; to restrain; to regulate; to govern;
      to overpower.
            Give me a staff of honor for mine age, But not a
            scepter to control the world.         --Shak.
            I feel my virtue struggling in my soul: But stronger
            passion does its power control.       --Dryden.
   Syn: To restrain; rule; govern; manage; guide; regulate;
        hinder; direct; check; curb; counteract; subdue.
   

3. \Con*trol"\, n.
   1. (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.
   2. (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.
   

4. \ (A["e]ronautics)
   Any system of rudders by which the pilot can exert a turning
   moment about each of the three rectangular axes of an
   a["e]roplane or airship.
   

(Or "ctrl", "^") One (or a pair) of modifier keys found on all modern keyboards. If the control key is held down while pressing and releasing certain other keys then a "control character" is generated, e.g. holding control and hitting "A" generates control-A (ASCII code 1). The ASCII code for the control character is generally 64 less than that for the unmodified character.

The control key does not generate any character on its own but most modern keyboards and operating systems allow a program to tell whether each of the individual keys on the keyboard (including modifier keys) is pressed at any time.

Control characters mostly have some kind of "non-printing" effect on the output such as ringing the bell (Control-G) or advancing to the next line (Control-J). Most have alternative names suggesting these functions (Bell, Line Feed, etc.).

See ASCII character table.