(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"
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"
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"
the economic policy of controlling or limiting or curbing prices or wages etc.; "they wanted to repeal all the legislation that imposed economic controls"
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"
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"
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"
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"
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"
verify or regulate by conducting a parallel experiment or comparing with another standard, of scientific experiments; "Are you controlling for the temperature?"
From The Free On-line Dictionary of Computing: (http://www.foldoc.org/, Editor Denis Howe)
(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.).