We found 15 dictionaries that define the word in a flash:

General (10 matching dictionaries)

1. in a flash: Merriam-Webster
2. in a flash: Oxford Learner's Dictionaries
3. in a flash: Vocabulary.com
4. in a flash: Cambridge Advanced Learner's Dictionary
5. in a flash: Wiktionary
6. in a flash: Dictionary.com
7. in a flash: Rhymezone
8. in a flash: FreeDictionary.org
9. in a flash: Mnemonic Dictionary
10. in a flash: TheFreeDictionary.com

Business (2 matching dictionaries)

11. in a flash: Legal dictionary
12. in a flash: Financial dictionary

Computing (1 matching dictionary)

13. in a flash: Encyclopedia

Medicine (1 matching dictionary)

14. in a flash: Medical dictionary

Miscellaneous (1 matching dictionary)

15. in a flash: Idioms

Definitions from WordNet (in a flash) ▸ adverb:  without any delay Phrases: take off in a flash, in a flash of brilliance, more... ▸ Words similar to in a flash ▸ Usage examples for in a flash ▸ Idioms related to in a flash ▸ Wikipedia articles (New!) ▸ Words that often appear near in a flash ▸ Rhymes of in a flash ▸ Invented words related to in a flash