closed-circuit television
noun [ U ] uk/ˌkləʊzd.sɜː.kɪt ˈtel.ɪ.vɪʒ.ən/ us/ˌkloʊzd.sɝːkɪt ˈtel.ə.vɪʒ.ən/ (abbreviation CCTV)
闭路电视（常设置于商店以防窃贼）
a system that sends television signals to a limited number of screens and is often used in shops as protection against thieves