surveillance

UK: /sə^rˈveɪləns/ US: /sɚˈveɪləns/ ,(sər vā′ləns, -vāl′yəns)

WordReference Random House Learner's Dictionary of American English © 2026

sur•veil•lance /sɚˈveɪləns/   n. [uncountable]

1. a watch kept over someone or something, esp. over a suspect, prisoner, etc.:
   under police surveillance.

WordReference Random House Unabridged Dictionary of American English © 2026

sur•veil•lance  (sər vā′ləns, -vāl′yəns), n. 

1. a watch kept over a person, group, etc., esp. over a suspect, prisoner, or the like:
   The suspects were under police surveillance.
2. supervision or superintendence.

• Latin vigilāre to watch; see vigil) + -ance -ance
• French, equivalent. to surveill(er) to watch over (sur- sur-¹ + veiller
• 1790–1800

Collins Concise English Dictionary © HarperCollins Publishers::

surveillance / sɜːˈveɪləns/ noun

1. close observation or supervision maintained over a person, group, etc, esp one in custody or under suspicion

Etymology: 19th Century: from French, from surveiller to watch over, from sur-¹ + veiller to keep watch (from Latin vigilāre; see vigil)

surˈveillant adjective , noun