Closed Circuit TeleVision. A television system intended as a 'closed' system, rather than broadcast, to be viewed by only a very limited number of viewers e.g. 1 camera to 1 monitor in its simplest form.
Found on http://www.zoo.co.uk/~z0001325/Glossary.html
Closed Circuit Television - commonly refers to security cameras, that record on to a tape and/or monitored by a control centre.
Found on https://www.encyclo.co.uk/local/20845