We found 42 dictionaries that define the word caffeine:

General (25 matching dictionaries)

1. caffeine: Merriam-Webster
2. caffeine: Oxford Learner's Dictionaries
3. caffeine: American Heritage Dictionary of the English Language
4. caffeine: Collins English Dictionary
5. caffeine: Vocabulary.com
6. Caffeine, caffeine: Wordnik
7. caffeine: Cambridge Advanced Learner's Dictionary
8. caffeine: Wiktionary
9. caffeine: Webster's New World College Dictionary, 4th Ed.
10. caffeine (caffein): The Wordsmyth English Dictionary-Thesaurus
11. caffeine: Infoplease Dictionary
12. caffeine: Dictionary.com
13. caffeine: Online Etymology Dictionary
14. caffeine: Cambridge Essential American English Dictionary
15. Caffeine (data page), Caffeine (disambiguation), Caffeine (film), Caffeine (service), Caffeine (video game), Caffeine: Wikipedia, the Free Encyclopedia
16. Caffeine: Online Plain Text English Dictionary
17. caffeine: Webster's Revised Unabridged, 1913 Edition
18. caffeine: Rhymezone
19. caffeine: AllWords.com Multi-Lingual Dictionary
20. caffeine: FreeDictionary.org
21. caffeine: Mnemonic Dictionary
22. caffeine: TheFreeDictionary.com
23. caffeine: Longman Dictionary of Contemporary English

Art (2 matching dictionaries)

24. Epicurus.com Tea Glossary (No longer online)
25. Epicurus.com Coffee Glossary (No longer online)

Computing (1 matching dictionary)

26. caffeine: Encyclopedia

Medicine (11 matching dictionaries)

27. caffeine: Merriam-Webster Medical Dictionary
28. Dorland's Illustrated Medical Dictionary (No longer online)
29. Caffeine: MedTerms.com Medical Dictionary
30. Medical Dictionary (No longer online)
31. Caffeine: Merck Manuals
32. online medical dictionary (No longer online)
33. caffeine: Dictionary of Cancer Terms
34. caffeine: Parents' Common Sense Encyclopedia
35. caffeine: Medical dictionary
36. Caffeine: Drug Medical Dictionary
37. Hyperdictionary (No longer online)

Sports (1 matching dictionary)

38. Caffeine: Body Building

Tech (2 matching dictionaries)

39. Caffeine: Coffee Glossary
40. Chemical Fact Sheet (No longer online)

(Note: See caffeines as well.)

Definitions from Wiktionary ( ) ▸ noun:  An alkaloid, C₈H₁₀N₄O₂, found naturally in tea and coffee plants, which acts as a mild stimulant on the central nervous system. Similar: caffein, caffiene, theine, mateine, caffeol, catechine, caffeate, caffoline, cafestol, theanine, more... Opposite: decaf, decaffeinated Types: coffee, tea, energy drink, soda, chocolate, more... Phrases: caffeine intoxication, caffeine free, Caffeine citrate, caffeine pills, caffeine addict, more... Adjectives: much, avoid, less, excessive, pure, citrated, enough, excess, dietary, alkaloid, intravenous Colors:     brown,     black,     dark brown,     espresso,     mocha, more... ▸ Word origin ▸ Words similar to caffeine ▸ Usage examples for caffeine ▸ Idioms related to caffeine ▸ Wikipedia articles (New!) ▸ Popular adjectives describing caffeine ▸ Words that often appear near caffeine ▸ Rhymes of caffeine ▸ Invented words related to caffeine