[n] - a closed-circuit television system used to maintain close observation of a person or group
The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community.
A series of monitoring devices designed to check on environmental conditions. 
noun a closed-circuit television system used to maintain close observation of a person or group
A vaccine consisting mainly of synthetic peptides or carbohydrates as antigens. They are often considered to be safer than vaccines from bacterial cultures.