subtitle
US /ˈsʌbˌtaɪ.t̬əl/
UK /ˈsʌbˌtaɪ.t̬əl/

1.
a secondary title of a book, article, or other publication
:
•
The book had an intriguing main title and a descriptive subtitle.
•
Each chapter began with a clear heading and a brief subtitle.
2.
a caption displayed at the bottom of a cinema or television screen that translates or transcribes the dialogue or narrative
:
•
Turn on the subtitles so we can understand the foreign film.
•
The news broadcast included closed subtitles for the hearing impaired.
1.
provide (a film or broadcast) with subtitles
:
•
They decided to subtitle the documentary for international release.
•
It takes a lot of effort to accurately subtitle a live broadcast.