Definition of "surveillance" in English

noun

1. Close observation of an individual or group; person or persons under suspicion.

2. Continuous monitoring of disease occurrence for example.

3. (military, espionage) Systematic observation of places and people by visual, aural, electronic, photographic or other means.

4. (law) In criminal law, an investigation process by which police gather evidence about crimes, or suspected crime, through continued observation of persons or places.