General Synonyms:
* Title: A heading or short description at the top of a document, article, or image.
* Heading: A title or a brief descriptive phrase at the beginning of a section of text.
* Subtitle: A secondary title that clarifies or expands on the main title.
* Legend: An explanatory list of symbols or abbreviations used in a diagram, map, or chart.
* Label: A short description attached to an image, object, or person for identification.
* Description: A detailed account of something, including its characteristics and features.
* Explanation: A statement that makes something clear or understandable.
More Specific Synonyms:
* Cutline: A short caption accompanying a photograph.
* Callout: A caption used to highlight specific elements in an image.
* Transcript: A written record of the words spoken in a video or audio recording.
* Subtitle: A written translation of the dialogue in a film or video.
The best synonym for "caption" will depend on the specific context and the intended meaning.