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tr.v. con·trolled, con·trol·ling, con·trols
1. To exercise authoritative or dominating influence over; direct: The majority party controls the legislative agenda. See Synonyms at conduct.
2. To adjust to a requirement; regulate: rules that control trading on the stock market; valves that control the flow of water.
3. To hold in restraint; check: struggled to control my temper.
4. To reduce or prevent the spread of: used a pesticide to control insects; controlled the fire by dousing it with water.
a. To verify or regulate (a scientific experiment) by conducting a parallel experiment or by comparing with another standard.
b. To verify (a financial account, for example) by using a duplicate register for comparison.
1. Authority or ability to manage or direct: lost control of the skidding car; the leaders in control of the country.
2. One that controls; a controlling agent, device, or organization.
a. An instrument.
b. controls A set of such instruments.
4. A restraining device, measure, or limit; a curb: a control on prices; price controls.
a. A standard of comparison for checking or verifying the results of a scientific experiment.
b. An individual or group used as a standard of comparison in a scientific experiment, as a group of subjects given an inactive substance in an experiment testing a new drug administered to another group of subjects.
6. An intelligence agent who supervises or instructs another agent.
7. A spirit presumed to speak or act through a medium.
[Middle English controllen, from Anglo-Norman contreroller, from Medieval Latin contrārotulāre, to check by duplicate register, from contrārotulus, duplicate register : Latin contrā-, contra- + Latin rotulus, roll, diminutive of rota, wheel; see ret- in Indo-European roots.]