a title or explanation for a picture or illustration, esp. in a magazine.

a heading or title, as of a chapter, article, or page.

Movies, Television . the title of a scene, the text of a speech, etc., superimposed on the film and projected onto the screen.

Law . the heading of a legal document stating the time, place, etc., of execution or performance.

to supply a caption or captions for; entitle

to caption a photograph.

noun

explanation , head , inscription , legend , rubric , subtitle , title , underline , cutline , heading , headline