We found 14 dictionaries that define the word captioning:

General (7 matching dictionaries)

1. captioning: Merriam-Webster
2. captioning: Collins English Dictionary
3. captioning: Vocabulary.com
4. Captioning, captioning: Wordnik
5. captioning: Wiktionary
6. captioning: Dictionary.com
7. captioning: TheFreeDictionary.com

Art (1 matching dictionary)

8. Encyclopedia of Television (No longer online)

Business (1 matching dictionary)

9. captioning: Legal dictionary

Computing (1 matching dictionary)

10. captioning: Encyclopedia

Medicine (4 matching dictionaries)

11. Captioning: MedTerms.com Medical Dictionary
12. Health and Wellness Dictionary (No longer online)
13. Captioning: Drug Medical Dictionary
14. Hyperdictionary (No longer online)

(Note: See caption as well.)

Definitions from Wiktionary (captioning) ▸ noun:  The act of assigning a caption. Similar: subtitle, legend, tagging, annotation, commentation, attribution, cueing, titling, commenting, attrib., more... Opposite: uncaptioned, without captions, unmarked Phrases: closed captioning, more... ▸ Words similar to captioning ▸ Usage examples for captioning ▸ Idioms related to captioning ▸ Wikipedia articles (New!) ▸ Popular adjectives describing captioning ▸ Words that often appear near captioning ▸ Rhymes of captioning ▸ Invented words related to captioning