1 (subtitles) captions displayed at the bottom of a cinema or television screen that translate or transcribe the dialogue or narrative:films in foreign languages with English subtitles
2a subordinate title of a published work or article giving additional information about its content:the book had now acquired its final title with a qualifying subtitle
verb
[with object]
1provide (a film or programme) with subtitles:much of the film is subtitled
2provide (a published work or article) with a subtitle:the novel was aptly subtitled
subtitle in other Oxford dictionaries
Definition of subtitle in the US English dictionary