CCTV is the written short form of closed-circuit television: cameras that send pictures to a small set of screens, not to every television in the country. Shops, stations, schools, and streets use CCTV so staff or the police can watch what is happening. “Closed circuit” is the old technical idea — the signal goes round a private loop, not out as a broadcast. Today the pictures often travel over computer networks, but people still say CCTV for those security cameras.

CCTV is the written short form of closed-circuit televisionCCTV 是 closed-circuit television，也就是閉路電視的縮寫: cameras that send pictures to a small set of screens攝影機把畫面送到一小組螢幕上, not to every television in the country而不是送到全國每一台電視. Shops, stations, schools, and streets use CCTV商店、車站、學校、街道都會用 CCTV so staff or the police can watch what is happening讓工作人員或警察可以看到發生了什麼事. "Closed circuit" is the old technical idea"closed circuit"，也就是閉路，是舊時的技術概念 — the signal goes round a private loop訊號是在一個私有的迴路裡繞, not out as a broadcast而不是像廣播那樣播放出去. Today the pictures often travel over computer networks現在畫面常常是透過電腦網路傳送, but people still say CCTV for those security cameras但大家還是把那些監視攝影機叫做 CCTV.

You see the letters on warning signs, especially in Britain (“CCTV in operation”). Americans more often just say “security cameras.” In speech, Taiwanese students usually say 監視器, even when a sign writes CCTV.

You see the letters on warning signs你會在警告標誌上看到這幾個字母, especially in Britain尤其是在英國, "CCTV in operation"標誌上常寫 "CCTV in operation"，意思是監視中. Americans more often just say "security cameras."美國人比較常直接說 "security cameras." In speech口語裡, Taiwanese students usually say 監視器台灣學生通常說「監視器」, even when a sign writes CCTV即使標誌上寫的是 CCTV.

One big trap: in Chinese, CCTV is also the usual English short name for China Central Television (央視). Same letters, completely different thing.

One big trap有一個很大的陷阱: in Chinese在中文裡, CCTV is also the usual English short name for China Central Television (央視)CCTV 也是中國中央電視台，也就是央視，常用的英文簡稱. Same letters, completely different thing一樣的字母，完全不同的東西.