<p><strong>Noun</strong></p><ul><li>a watch kept over a person, group, etc., especially over a suspect, prisoner, or the like: The suspects were under police surveillance.</li><li>continuous observation of a place, person, group, or ongoing activity in order to gather information: electronic surveillance.</li><li>video cameras used for covert surveillance.</li><li>attentive observation, as to oversee and direct someone or something: increased surveillance of patients with chronic liver disease.</li></ul>