a variable in a model controlled by an agent in order to optimize a specific objective
A variable whose value determines if a controlled statement is to be executed; typically, a variable declared in the first expression of a for-statement.
The variable within a control system that is manipulated to achieve a desired response in the output variable.
Control variables are those variables that are not changed throughout the trials in an experiment because the experimenter is not interested in the effect of that variable being changed for that particular experiment. (In other words, control variables are extraneous factors, possibly affecting the experiment, that are kept constant so as to minimize their effects on the outcome.) An example of a control variable in an experiment might be keeping the pressure constant in an experiment designed to test the effects of temperature on bacterial growth.