|close observation or supervision maintained over a person, group, etc, esp one in custody or under suspicion|
|[C19: from French, from surveiller to watch over, from |
surveillance sur·veil·lance (sər-vā'ləns)
Close observation of a person or group, especially one under suspicion.
The act of observing or the condition of being observed.
The collection, collation, analysis, and dissemination of data.
A type of observational study that involves continuous monitoring of disease occurrence within a population.