1. In clinical trials comparing two or more interventions, a subject in the comparison group who is offered a placebo, receives no treatment or receives standard care.

2. In case-control studies, a person in the comparison group who is without the disease or clinical state of interest.

3. statistical control
In statistics control, a procedure to adjust the results to take into account extraneous factors that could distort them.

4. infection control
In public health, a programme aimed at reducing the extent or the consequences of an infectious disease.