Surveillance (noun)

1. The act of closely observing or monitoring a person or group.
2. The act of keeping a watchful eye on a person or group.
3. The act of keeping a close watch on a place or situation.
4. The practice of keeping an eye on something or someone in order to prevent or detect criminal activity.
5. The act of monitoring something or someone to ensure that they comply with rules or laws.

Origin:

From middle french surveillance, from latin surveillantia ("watchfulness"), from surveillantem, present participle of surveillare ("to watch over"), from super- ("over") + vigilare ("to watc.h")

Examples:

1. The government has increased surveillance of suspected terrorists.
2. The company has surveillance cameras installed for security.
3. The city has increased surveillance of the downtown area.
4. The surveillance of the border is important for national security.
5. The surveillance of the employees is necessary to detect fraud.