surveillance

noun

sur·​veil·​lance sər-ˈvā-lən(t)s 

also

-ˈvāl-yən(t)s 

or

-ˈvā-ən(t)s 

: close watch kept over someone or something (as by a detective)

also : supervision see also immune surveillance

Synonyms

• stewardship
• supervision
• oversight
• management
• control
• policing
• regulation

Examples of surveillance in a Sentence

government surveillance of suspected terrorists

The bank robbery was recorded by surveillance video cameras.

Recent Examples on the Web

The institute also launched a wastewater surveillance project, geared at monitoring and anticipating disease trends in communities. —Maggie Menderski, Louisville Courier Journal, 26 Oct. 2025

Now, officials are investigating why her mom drove them in a rental car from California to Nebraska and why the 9-year-old was apparently wearing a wig in surveillance photos captured earlier this month. —Michelle Watson, CNN Money, 26 Oct. 2025

Detectives on Saturday said Richard Lund, 43, and Asia Morton, 25, were taken into custody after weeks of tracking leads, reviewing surveillance footage and piecing together digital evidence. —Santa Rosa Press Democrat, Mercury News, 26 Oct. 2025

Investigators are looking for witnesses and surveillance video that might have captured the collision, said police Officer Sarah Foster. —Karen Kucher, San Diego Union-Tribune, 26 Oct. 2025

Word History

Etymology

French, from surveiller to watch over, from sur- + veiller to watch, from Old French veillier, from Latin vigilare, from vigil watchful — more at vigil

First Known Use

1802, in the meaning defined above

Phrases Containing surveillance

• counter-surveillance
• electronic surveillance
• immune surveillance
• immunological surveillance
• keep under surveillance

Kids Definition

surveillance

noun

sur·​veil·​lance sər-ˈvā-lən(t)s 

 also  -ˈvāl-yən(t)s,

 or  -ˈvā-ən(t)s

: close watch

under surveillance

Medical Definition

surveillance

noun

sur·​veil·​lance

sər-ˈvā-lən(t)s also -ˈvāl-yən(t)s or -ˈvā-ən(t)s

: close and continuous observation or testing

serological surveillance

see immune surveillance