closed-circuit television
noun /ˌkləʊzd ˌsɜːkɪt ˈtelɪvɪʒn/
  /ˌkləʊzd ˌsɜːrkɪt ˈtelɪvɪʒn/
 [uncountable] (abbreviation CCTV)
- a television system that works within a limited area, for example a public building, especially to protect it from crime闭路电视 Collocations DictionaryClosed-circuit television is used before these nouns:- surveillance