SURVEILLANCE
surveillance
(noun) close observation of a person or group (usually by the police)
Source: WordNet® 3.1
Etymology
Noun
surveillance (countable and uncountable, plural surveillances)
Close observation of an individual or group; person or persons under suspicion.
Continuous monitoring of disease occurrence for example.
(military, espionage) Systematic observation of places and people by visual, aural, electronic, photographic or other means.
(legal) In criminal law, an investigation process by which police gather evidence about crimes, or suspected crime, through continued observation of persons or places.
Source: Wiktionary
Sur*veil"lance, n. Etym: [F., fr. surveiller to watch over; sur over
+ veiller to watch, L. vigilare. See Sur-, and Vigil.]
Definition: Oversight; watch; inspection; supervision.
That sort of surveillance of which . . . the young have accused the
old. Sir W. Scott.
Source: Webster’s Unabridged Dictionary 1913 Edition