0 the key on a computer keyboard that usually has "Ctrl" printed on it and that is used along with other keys to do particular operations
1 a key on a computer keyboard, usually with ‘Ctrl’ printed on it, which you press with other keys to make the computer do a particular thing:
The following sections provide evidence pertinent to assessing whether electoral reform has changed the factions' ability to control key resources.
A multinational corporation does not seek to control key industries in host countries.
The policy is to control key fares for commuters and other users rather than to regulate every fare.
I refer to the workers who control key industries.
Other systems translate these keys into control characters when the control key is held down.
Others leave the control key in the lower-left corner of the keyboard, and press it using the side of their palm.
The process can be repeated as many times as desired, as long as the control key is held down.
The control key is most frequently associated with handy modifier keystrokes such as cut-and-paste, or application shortcuts such as control-s to save.