closed caption
Closed caption (noun) means On-screen text of a video's dialogue together with speaker labels and descriptions of relevant sounds, which the viewer can switch on or off — designed so that deaf and hard-of-hearing viewers get the audio information as well as the words. Example: “Turn on closed captions if you cannot hear the dialogue over the music.”
How to use closed caption
Learner’s notesIn plain EnglishText on screen showing what is being said and heard, which you can switch on or off.
Neutral; standard in broadcasting, accessibility law and video platforms. Chiefly American in origin but now global.
The activity is closed captioning and the plural noun is usually closed captions. American English tends to write closed captioning where British English says subtitling.
Trace the full origin ↓Fill the gap
Can you complete this real example?
Turn on _____ if you cannot hear the dialogue over the music.
Etymology
Closed because the text is carried hidden in the signal and must be decoded and switched on by the viewer, as opposed to open captions which are burned permanently into the picture.