| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
control con·trol (kən-trōl')
v. con·trolled, con·trol·ling, con·trols
To verify or regulate a scientific experiment by conducting a parallel experiment or by comparing with another standard.
To hold in restraint; check.
A standard of comparison for checking or verifying the results of an experiment.
An individual or group used as a standard of comparison in a control experiment.
| control (kən-trōl') Pronunciation Key
A standard of comparison for checking or verifying the results of an experiment. In an experiment to test the effectiveness of a new drug, for example, one group of subjects (the control group) receives an inactive substance or placebo , while a comparison group receives the drug being tested. |